TOEFL® Word List

Definition: The visual images and symbols used in a work of art or the study or interpretation of these:

Example sentences:

• Ever since, lions have been portrayed in art, myth and iconography as powerful symbols of solar strength, supremacy, glory, light and brilliance.

Definition: (Of rock) having solidified from lava or magma

Example senences:

• The occurrence of these felsic extrusive igneous rocks potentially provides key information on the complex interplay of magmatism and tectonics.

Definition: Light up

Example sentences:

• A great flash of lightning illuminated the world outside, showing the trees dark against the night sky.

Definition: A thing intended to simulate or copy something else

Example senences:

• These works are often replicas or imitations of ancient Greek and Roman art. Surely, there could be imitations and really good reproductions, but these cannot be considered original art

Definition: Resistant to a particular infection or toxin owing to the presence of specific antibodies or sensitized white blood cells

Example sentences:

• Vaccinations allow you to become immune to an infection without having the illness first.

Definition: Make (a person or animal) immune to infection, typically by inoculation

Example sentences:

• Stray dogs are carefully controlled, household dogs are immunized, and rabies vaccination is widely available.

If you impart information or knowledge to people, you tell it to them.

Example sentences:

• The ability to impart knowledge and command respect is the essential qualification for teachers.
• A teacher's most challenging role is not to impart knowledge but to relate to students the value of learning.
• The people who are in favor of the schools, dealing with traditional subjects such as history believe that the children are oblivious of their career path at tender ages, therefore, imparting any specific skill or job oriented knowledge may go in vain.

To impede something is to delay or block its progress or movement. When we use the word 'impede', we are talking about long-term obstacles or problems that cannot be solved in a short period of time. Here are example sentences:

Example sentences:

• Economic growth is being impeded by government regulations.
• Fallen rock is impeding the progress of rescue workers.
• The continued war impeded the country’s recovery.

To implicate someone means to show or claim that they were involved in something wrong or criminal.

Definition: making a strong or vivid impression

Example sentences:

• Eric showed impressive speed in the open field, rushing for 184 yards on just eight carries in his college debut.
• This very early and inventive way for flowering plants to manage their reproduction so early in their evolution is impressive.

Definition: in an impulsive or impetuous way; without taking cautions

Example sentences:

• Research suggests that feeling “too positive” can interfere with decision making and cause people to neglect environmental threats and act impulsively.
• This type of a snack can help you avoid becoming so hungry during the day that you impulsively over-consume calories at the next meal.

The phrase "in retrospect" means when thinking about the past or something that happened in the past​ Here are example sentences:

• In retrospect, I should have realized I was going to fail the class.
• In retrospect, I made the right decision.​

When something happens by accident, it's inadvertent, or unintentional. .When your actions are inadvertent you're not paying attention to their consequences.

Example of inadvertent usage:

• I’m sorry I forgot to pay rent that was inadvertent.​
• The gas company assured you that the error in your bill was inadvertent and that they would fix it.

Definition: Not subject to being taken away from or given away by the possessor:

Example sentences:

• One of the inalienable rights of British subjects in 1840 was that their beliefs were to be respected. We know what it is like to assert that the right to sovereignty, independence and unity is inalienable and indefeasible.

The adjective inaudible describes something that is impossible to hear. You are likely to see this word in academic textbooks. The phrase ‘be inaudible to someone’ is often used. For example:

• Sounds of frequencies higher than 20,000 Hz are inaudible to humans, while dogs can hear sounds up to a frequency of 45,000 Hz.
• Ultrasound is an inaudible sound wave to humans.

Inaudible is the negated form of audible, so instead of using “dogs can hear” you could form a sentence like this:

• Sounds up to a frequency of 45,000 Hz are audible to dogs.

Definition: The occurrence, rate, or frequency of a disease, crime, or other undesirable thing

Example sentences:

• Trees can help reduce the incidence of respiratory diseases as well as lung cancer.

Definition: Take in or contain (something) as part of a whole; Constitute (a company, city, or other organization) as a legal corporation:

Example sentences:

• Nine previously unreported markers were incorporated into the integrated map
• The defendant corporation was incorporated under, and subsists under, the laws of Ontario and has its head office in the City of Toronto

Difference between “increasing” and “increased”

When something is increasing, it means that this thing continues to rise; however, when something has increased, it means that thing has now stopped increasing.

Let’s further look at the difference between “increasing” and “increased” in the following example sentences:

• Lately, scientists have observed “increasing” pollution in the water supply.
• Lately, scientists have observed “increased” pollution in the water supply.

As you just saw, both words can be used in the sentence; but "increasing" would suggest the pollution to the water supply continues to rise, whereas "increased" would suggest it has now stopped.

Now that we have understood the difference between “increased” and “increasing”, I would like you to stop and think about how the words “increased” or “increasing” can be used in the blank space of the following sentence:

• Due to ____ competition, organizations are now operating more efficiently.

Let’s take a look now!

If the competition is still increasing, use increasing. It would mean that the increase is occurring now and is expected to continue. However, if the competition has already increased, and you want to emphasize that fact, use increased.

Let's look at more example sentences using "increasing" and "increased".

• Former agricultural land near large cities has been converted to urban use at an increasing rate.       
• New obesogenic chemicals are being identified at an increasing rate.
• These symptoms are associated with an increased risk of heart disease.

Incubate means to sit on egg in order to keep them warm before they hatch. Example sentences are:

• Birds incubate their eggs to keep them at an appropriate temperature.
• When most birds incubate eggs, the females often produce high levels of prolactin, a hormone involved in parental behavior.
• In monogamous species, both the male and female build the nest and incubate eggs.

In a laboratory, to incubate means to keep (eggs, bacteria, or embryos) at a suitable temperature so that they develop. For example:

• The embryos are incubated in the laboratory at 80°C.

To indicate means to point something out or to present evidence. There are two patterns:

• indicate that + Subject + Verb
• indicate + Noun

Here are example sentences:

• Estimates indicate that more than 60 percent of the yearly retail sales in the U.S. are credit transactions.
• Evidence indicates that people have always been predominantly right-handed.
• The drastic disappearance of Foraminifera in these layers of rock indicated that something had happened at the boundary between the Cretaceous and Tertiary periods.
• The drastic decline in the numbers of amphibians worldwide indicates the global pollution of water and air.
• Record profits in the retail market indicate a boom in the economy.
• An increase in crime indicates a decline in moral standards.
• The importance of the sun in the Rameses cartouche is vital because it indicates the language of the scribes.

The word “indicate” can also be used without an object. The example below highlights it uses without an object.

• You forgot to indicate. (This means you forgot to signal before you made your turn when driving.)

Use the word indicative when you want to show that something is suggestive or serves as a sign of something. 

The phrase "be indicative of" basically means "is an indication of". Therefore, when paraphrasing, you can use "be indicative of" or "is an indication of" instead of "indicate". Let's look at the following example:

• The drastic decline in the numbers of amphibians worldwide indicates the global pollution of water and air.

Can be paraphrased to 

• The drastic decline in the numbers of amphibians worldwide is indicative of the global pollution of water and air. = 
• The drastic decline in the numbers of amphibians worldwide is an indication of the global pollution of water and air.

Here are more example sentences:

• Thin tree rings are indicative of slow growth. [=Thin tree rings indicate that a tree has grown slowly]
• Provocative images of the media are the indicative of the vibrant competitions in the media.

Definition: showing no care or concern in attitude or action

Example sentences:

• The research founds out that people can feel compelled to analyse old memories or get new information, meaning staying indifferent can actually require effort.
• People fear task and results-driven organizations that are indifferent to the human costs of their actions.

Definition: failing to make or recognize distinctions; not marked by fine distinctions

Example sentences:

• Treaties banning some extremely indiscriminate weapons—poison gas, landmines, cluster bombs—have had some success.
• While malaria is indiscriminate, the heaviest toll is on the poorest and most vulnerable communities.

Definition: incapable of being avoided or prevented

Example sentences:

• Change is inevitable, so preparation is key to maneuver fluidly with the changes.
• Virtually every parent has faced the inevitable problem of disciplining a child for conduct that merely replicates the parent’s own actions.

Something inexplicable can't be explained. It doesn't make sense. You don't want to come to the beach on the most beautiful day of the year? That's inexplicable! Remember that “in” can mean “not” and explicable sounds like explainable, which helps you remember that inexplicable means “not explainable.” Used in a sentence, “The jury’s decision was inexplicable, as there is no way he was guilty!”

Example sentences:

• He had a series of seemingly inexplicable accidents.
• His behavior was extraordinary and inexplicable.

Definition: The process of infecting or the state of being infected

Example sentences:

• This causes the skin to blister on contact, which can result in infection, sepsis, and death

Definition: the state of being invaded or overrun by parasite

Example sentences:

• Indeed, worm infestations, lice and a variety of other health problems plague the residents of the water villages.

Definition: A general increase in prices and fall in the purchasing value of money

Example sentences:

• In a downward inflation trend, salary expectations lag the decreases in inflation. In December he indicated that he was concerned about inflation and the excessive risk taking in the markets.

Influential means having or exercising influence or power over someone or something. Here are example sentences:

• An influential newspaper will make people change their opinions about something.
• The bible is considered a very influential book.
• Influential books can affect someone’s outlook on life.
• Self-help books are usually very influential.

If your grandfather worked his whole life in hospitals and inspired you to become a doctor, you could describe your grandfather as very influential in your life. 

The phrase "be influential in" is often used. Here is an example

• She has been influential in establishing programs to help the poor.

In addition, sometimes measure words such as highly/very or enormously/extremely are used before the word: influential. Some example sentences include:

• a highly/very influential book
• She became an (enormously/extremely) influential critic/writer.

The adjective informative is used to describe something that gives you useful information. When something is informative, it's usually educational and full of facts — like an informative text book, an informative documentary, or an informative tour of the Hindu temples of northern India. This word comes in handy in TOEFL independent writing and speaking 1 tasks.

Definition: (Of equipment or techniques) using or concerned with infrared radiation:

Example sentences:

• But if that storm clears in time, the jets were going to get out with some infrared equipment and help with the search starting tomorrow

Something ingenious shows creativity and inventiveness. If someone compares you to Einstein, they're implying that you, too, are ingenious. It started off meaning someone who was talented or incredibly smart but has come to mean inventive, or clever. If you can solve 746,643 * 67,389 in your head, people might call you a math genius. But if you come up with a way to turn water into fuel, you will be praised as ingenious. 

Example sentences:

• Gautier's solution to the puzzle is ingenious.
• She was ingenious in finding ways to work more quickly.
• It was ingenious of him to arrange the schedule so precisely.

Definition: a component of a mixture or compound

Example sentences:

• Restaurant owners say healthy-eating initiatives should focus on diet as a whole, not on particular ingredients or foods.
• Firing up the grill can be one of the simplest strategies for delicious, healthy summer eating – if you use the right ingredients and techniques.

An inhabitable place is a place that is suitable to live in. An example in a sentence:

•  As our Sun gets older, it will get larger and warmer, eventually leading to the Earth becoming inhabitable.

An uninhabitable place is a place that is not suitable to live in. An example in a sentence:

• If there's no roof then the house is uninhabitable.                                                             

Inherently is in a natural manner. Some people are inherently kind, which means that they don’t have to put any effort into being nice to other people, it is just comes naturally to them. On the flip side, you may be inherently shy. An example in a sentence:

• The teacher was inherently kind, so the students loved her from the start.

An inhospitable area is not suitable for humans to live in. An example in a sentence:

• Tibetans still form a majority of people living in the inhospitable countryside.​

Definition: The action or process of innovating:

Example sentences:

• Innovation is crucial to the continuing success of any organization.

Definition: Too many to be counted (often used hyperbolically)

Example sentences:

• I sat surrounded by flowers and portraits and innumerable tributes to him.

"Inscribe" can have several meanings, but in most cases, it means to write something in a permanent or formal way. Inscribe can mean to carve, cut or etch into a material or surface, such as:

• The rock was inscribed with tribal markings.

It can also mean to mark with one’s signature:

• The doctor inscribed on the prescription for the patient.

Engrave and inscribe are synonyms, though you normally engrave into metal or stone.

Definition: A substance used for killing insects

Example sentences:

• Mites may be developing resistance to some of the currently used chemical insecticides.

Definition: Proceeding in a gradual, subtle way, but with harmful effects

Example senences:

• The obstruction and harassment is subtle but insidious and seriously affects the ability of the aid agencies to do their job.
• Sexually transmitted diseases can be insidious and sometimes without symptoms

Insightful is an adjective that is exhibiting insight or clear and deep perception. If you are insightful, you are confident and inquisitive. For example:

• One of the most important aspects of being an insightful leader is avoiding the pitfall of the obvious.

Insightful things make you ponder more than you normally would.  For example:

• The chapter was insightful to why the refugees felt that had to leave the camp.

Definition: Unable to pay debts owed:

Example sentences:

• China's banks are technically insolvent, with bad debts making up 45% of their loans, according to Standard & Poor's.
• If the employer is insolvent and unable to restore the funds the pension scheme will be able to claim compensation.

The adjective instant describes something that is happening right now, without delay. 

A synonym for “instant” is “instantaneous ” or  "immediate". However, most English speakers would say that something that is instantaneous happens even more quickly than something that is instant.  In addition, instantaneous is much less frequently used than instant, and it is a more formal word. It is used mostly to describe things that happen in concrete, academic, or scientific contexts.

Example sentences using the word instant:

• We got an almost instant response from the company.
• Computers have created a system for easy and instants communication.
• While personal cell phones have facilitated instant connections with people, texting is a cause of underdeveloped communication skills in children.
• Through email or various video chat websites, people can send instant messages or speak as if in person.
• The Internet provides instant access to an enormous amount of information.

Instant food or drink is dried, usually in the form of a powder, and can be prepared very quickly by adding hot water. 

• Instant coffee is bad for your health.

The following phrases are often used:

• in an instant = immediately
• for an instant = for a moment

Here are example sentences:

• For an instant, I forgot where I was.
• For a brief instant, I thought she was going to fall.
• The ride was over in an instant.
• It was all over in an instant.

The following collocations are often used:

• an instant hit/sensation/success
• an instant celebrity

Here are example sentences:

• The movie was an instant hit/sensation/success.
• He became an instant celebrity with the publication of his first novel.

A synonym for “instantly” is “instantaneously.” or "immediately". However, most English speakers would say something happens instantaneously happens even more quickly than something that happens instantly.  In addition, instantaneously is much less frequently used than instantly, and it is a more formal word. It is used mostly to describe things that happen in concrete, academic, or scientific contexts.

Example sentences with the word instantly:

• His voice is instantly recognizable.
• They instantly fell in love.
• Telephones allow people to talk over large distances instantly.

An instinct is something you don't need to learn — it happens naturally, without you even thinking about it. Babies cry by instinct, and ducks follow their mother by instinct. If you have an instinct for something, you are naturally good at it.

Example sentences:

• Her instincts told her that something was wrong. (This means she believed that something was wrong even though there was no obvious reason to believe it).
• I didn't have as strong a maternal instinct as some other mothers.
• The basis for training relies on the dog's natural instinct to hunt and retrieve.
• He always knew what time it was, as if by instinct.
• I acted purely on instinct.

COLLOCATIONS

deep/strong/powerful instinct

• He bent down, obeying a deep instinct to protect himself from danger.

a natural instinct

• I followed my natural instinct to run away.

somebody's first/initial instinct

• His first instinct was to try and hide.

somebody's gut instinct informal (=someone's first instinct)

• Her gut instinct about Jimmy had been right.

human instinct

• It's a natural human instinct to comfort someone who is unhappy.

animal instinct

• It's animal instinct to attack the leader of the herd when his strength begins to fail.

trust your instinct(s) (also rely on your instincts) (=believe that your instincts are correct)

• I've trusted my instincts in the past and they've usually been right.

Definition:

Example sentences:

In today’s environment of global communication and mass internet usage, reading is an imperative skill to communicate and thrive and has become instrumental to one’s success in today's competitive world.

She was instrumental in bringing about the prison reform act.

The informant’s tip-off was instrumental in the arrest of the serial killer.

Music genres include Christmas Pop, Rock, Classical, Instrumental, Jazz and Smooth.

Definition: The action of insulating something

Example sentences:

• You can keep your home warmer through insulation.

Tangible and intangible are antonyms. Tangible is something that you can touch or something that can be perceived by your senses. Normally, children are only encouraged by tangible rewards. 

If you say, “Wow! You did great” it won’t go very far with a seven-year-old. However, if you say “Wow! You did great!” and also give the child a sticker, they will likely be more excited because the sticker is tangible and something they can look at and feel.

On the contrary, intangible things can not be touch, felt, smelt or tasted. Feelings are intangible because even though you can’t feel them with your senses, you can feel them in your heart. For example, if you are sad, you aren’t able to pick up your sadness and throw it away. You also may feel a lot of joy from intangible things, such as a promotion. Even though your desk stays the same, your pride may be bursting at the seams.

Definition: Become or make more intense

Example sentences:

• The researchers say that increasing the amount of zirconium may intensify the color.
• The importance of the test will intensify the nervousness of the students

Definition: Occurring at irregular intervals; not continuous or steady

Example sentences:

• A geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapor phase which is steam.

Internalize means to accept or absorb an idea, opinion, belief, etc. so that it becomes part of yours. Here are example sentences

• Children internalize their parents' values.
• When learning math, you should internalize mathematical concepts.
• If you are a debater who internalizes a topic, then you know it inside and out
• One way to know that you're internalizing a topic correctly is when you're reading a textbook and you start to guess or ask about something the author is just about to talk about.
• To internalize the grammar, knowing and understanding the rules is one thing, but then indeed one needs to have access to a significant amount of “samples” of sentence structures to keep in mind on an unconscious level.

If you internalize your emotions or feelings, you do not allow them to show although you think about them. For example, if you are hurt but don’t tell anyone, you internalize the pain. Another situation could be if you are heartbroken because your boyfriend broke up with you, you may internalize those feelings, so no one knows you are sad.

Definition: Explain the meaning of (information or actions):

Example sentences:

• Most of the staff quoted in the book wanted to understand numerical measures of risk, and they reported feelings of inadequacy at the difficulties they had in interpreting information for patients.

New observations confirm that interstellar dust can come from explosions known as supernovae.

Definition: The action or process of intervening

Example sentences:

• The intervention by central banks is to correct or prevent long-run misalignments of exchange rates.

Definition: Exhilarating or exciting;(Of alcoholic drink or a drug) liable to cause intoxication.

Example sentences:

• Refrain from intoxicating drink and drugs which lead to carelessness.

Definition: cause to be interested or curious

Example sentences:

• As listeners, we’re meant to be intrigued by these secrets, even if their basis in reality is unclear.

Intrinsic means belonging to the essential nature of a thing. 

• The intrinsic brightness of a star. (Here intrinsic means occurring as a natural part of something.)

• Doing a job for only money is not intrinsic, and doing a job because you love it is intrinsic (This is because the motivation comes from within)

Let’s look at some more examples:

• If you like someone for intrinsic reasons, then you have no other motivation.

• He had intrinsic motivations for finishing school. (This means that he wasn’t finishing school so he could get a good job; he was finishing school because he enjoyed learning and wanted to prove to himself he could do it.)

The word intrinsic is often used with the preposition “to” as shown in the example below

• Creativity is intrinsic to human nature = Creativity belongs to the essential part of human nature. 

Definition: Causing disruption or annoyance through being unwelcome or uninvited:

Example sentences:

• That was an intrusive question

Definition: Never changing:

Example sentences:

• The invariable result is always supposed to be mass unemployment, industry collapse, and economic meltdown - until someone points out reality.

You use invasive to describe something undesirable which spreads very quickly and which is very difficult to stop from spreading like invasive species, invasive cancer, invasive pests.

Invasive species are plants or animals that are not native to an environment and steadily spread, sometimes taking over the native landscape.

Here are example sentences:

• Raccoons are an invasive species in Scotland.
• They found invasive cancer during a routine examination.
• An invasive pest can decimate unprotected crops.

Invasive can also mean intrusive. Something intrusive is invading your privacy. If someone asks you a million questions, especially personal questions, that's intrusive behavior. When photographers hound celebrities, they're being intrusive.

Let's look at an example using invasive:

•  I feel that keeping direct eye contact is less invasive than a handshake or a hug.

Definition: the work of inquiring into something thoroughly and systematically

Example sentences:

• The comprehensive investigation of the bank revealed no illegal activity.

Definition: Done without will or conscious control;(Especially of muscles or nerves) concerned in bodily processes that are not under the control of the will

Example sentences:

• The involuntary muscles are controlled by structures deep within the brain and the upper part of the spinal cord called the brain stem.

Definition: Not logical or reasonable

Example sentences:

• The more irrational and illogical someone becomes, the more logical and incisive I become

Definition: Supply water to (land or crops) to help growth, typically by means of channels.

Example sentences:

• While rainfall registers about 50 inches per year, growers often have to irrigate their crops during extended drought periods.

Definition: The ideas and manner of thinking characteristic of a group, social class, or individual

Example sentences:

• But these social ideologies were united in their underlying belief that economic progress was the way to go.

Definition: Catch fire or cause to catch fire

Example sentences:

• The wet weather put the dampeners on most of the grass fires that ignite during the usually drier summer month.

Definition: Lighting

Example sentences:

• General or background lighting provides an overall level of illumination when natural light levels are low. The basement was dank and dark with no windows and only a few strategically placed fluorescent lights for illumination.

Immense is an adjective that means very large in size, amount, or degree.

The following collocations are often used:

• immense amounts of something = enormous amount of something = vast amount of something
• immense pain
• immense talent
• immense fortune/wealth
• immense pressure
• immense popularity

Example sentences:

• Ragtime is a musical genre that is best known for its syncopated rhythms, and it enjoyed immense popularity between 1895-1918
• He inherited an immense fortune.
• Her movies continue to enjoy immense (or enormous) popularity.
• She is an artist of immense talent.
• I felt immense pain.
• They’ve spent immense amounts of money on building an enormous conservatory in their back garden.
• I’m under immense pressure at work.
• With immense relief, I stopped running.
• With a growing population and immense wealth, the ancient Romans developed great monuments and cities.
• The ocean releases immense amounts of heat into the atmosphere.

Definition: Make (a person or animal) immune to infection, typically by inoculation

Example sentences:

• We recorded use of preventive health services and immunisations at the final paediatric assessments.

An impact simply is the outcome or result of something.  The following patterns and expressions are commonly used with the noun impact. Note that A is the cause. B is the effect.

• The/One impact of A on ___ is B
• B is an/one impact of A on ___
• A has/have an impact on ____

The first and the second pattern describe what causes the effect - this is the A part -, and they define what the effect - B- is. Additionally, we use the preposition on to define the thing that is impacted by this cause and effect relationship. The third pattern only describes that something has an impact on something else, without actually defining the effect or consequence in detail.

Here are example sentences:

• One impact of advertising on the public is overconsumption.
• Overconsumption is one impact of advertising on the public.
• Advertising can have a significant impact on the public

When we use the noun ‘impact’, or ‘effect’, we often use positive adjectives like ‘positive’, ‘beneficial’ or negative adjectives like ‘negative’, ‘adverse’, ‘harmful’, ‘detrimental’ before it.

Let’s look at the following examples:

• One negative impact of social media on the society is that it leads to addiction.
• One positive impact of computers on society is that they bring convenience to our lives.
• Parasitic relationships can have beneficial or harmful effects on hosts.

We often use the third pattern, followed by the second pattern when we write a summary.

Here are examples:

• Globalization has many adverse impacts on developing countries. One negative impact is the acceleration of income inequalities. However, globalization can also have positive impacts on developing countries.One positive impact is that it creates greater opportunities for firms to tap into more and larger markets around the world.

• Nicotine, an addictive substance, has many harmful effects on our health. One detrimental effect of nicotine is that it causes lung diseases. Another adverse effect of nicotine is it causing damage to our brains.

Definition: free from undue bias or preconceived opinions

Example sentences:

• While consultants often claim that they provide an impartial assessment of a bank’s problems, they are also handpicked and paid by those same banks.

An impediment is anything that slows or blocks progress. It can refer to a physical thing, like a fallen tree in the road. It can also refer to things that can’t be seen. The preposition “to” is often used.   When we use the word 'impediment', we are talking about long-term obstacles or problems that cannot be solved in a short period of time. Here are example sentences:

• According to a number of teachers, the biggest impediment to working in a small town is the low salary paid to educators.
• The continued war is an impediment to the country’s recovery.
• The agreement is designed to remove impediments to trade between the two countries.
• The board was satisfied that there was no legal impediment to the merger of the two companies. 
• Fallen rock is an impediment to the progress of rescue.

Medically, an impediment is especially said to be a physical hindrance, such as a lisp or a stammer. Here are example sentences:​

• If someone has a reading impediment, it means that their reading strength has roadblocks for one reason or another. 
• Stammer is a physical impediment.
• John's slight speech impediment made it difficult for his mother to understand him.

An implication is something that is suggested, or happens, indirectly. When you left the gate open and the dog escaped, you were guilty by implication. "Implication has many different senses: Usually used in the plural, implications are effects or consequences that may happen in the future. You might ask, "What are the implications of our decision?"

Example sentences:

• We must consider the long-term implications of the new trade policies. (This means we must consider the effect the policies may have in the future)
• The closing of the factory has economic implications for the entire community
• The low level of current investment has serious implications for future economic growth.
• The research has far-reaching implications for medicine as a whole.
• In refusing to believe our story, he is saying by implication that we are lying.

Definition: in an improper way

Example sentences:

• The pointed attorneys have argued the judge improperly excluded certain evidence and testimony.

Definition: A constituent which impairs the purity of something

Example sentences:

• The impurities dissolve in lead and evaporate leaving behind silver and gold. Aluminium and lead are impurities frequently found in tap water.

Definition: something that cannot be reached or communicated with

Example senences:

• The company encrypts its data and takes other measures to ensure its information is secure and inaccessible by other competitors.

Inadvertently is an adverb that means "without knowledge or intent," like when you inadvertently take someone else's coat from the coatroom because it looks just like yours.

Example sentences using the word inadvertently:

• I inadvertently (meaning accidentally, mistakenly) dialed the wrong number.
• I inadvertently deleted your phone number
• She inadvertently told my husband about his surprise  party

Definition: Showing no sign of life; lifeless

Example sentences:

• In both photographs the inanimate face is shown in three-quarter profile facing right against a blank background.

Definition: uninterrupted in time and indefinitely long continuing

Example sentences:

• This incessant belching expels an impressive volume of greenhouse gases—mostly methane and carbon dioxide.
• Fourteen large fires are burning, mostly in the scorched northern half of the state, and California's incessant drought is only making matters worse.

Incomprehensible means it's difficult to understand and it might be impossible to explain. Many unfamiliar customs or rituals seem incomprehensible from a distance, for example, people who don’t wear shoes at all may find it incomprehensible why women would wear high heels. Used in a sentence, “It is incomprehensible why my family spent so much money on a vacation.”

Example sentences:

• I found his behavior utterly incomprehensible.
• It's incomprehensible to me that he could have acted that way.
• Her speech was almost incomprehensible.

The word increase can be a noun or a verb.

As a noun, it means a rise in the amount, number or value of something. 

An increase in something  = a rise in the amount, number or value of something. Remember the preposition is "in". Here are example sentences:

• Due to the increase in the burning of fossil fuels and nuclear testing in the 20th century, there was a significant increase in the level of carbon dioxide in our atmosphere.
• Last year, our school had an increase in enrollment.
• A number of scientific discoveries led to the dramatic increase in life expectancy.
• I expect an increase in wages.
• The construction will probably cause an increase in traffic delays.
• The city has experienced an increase in population.
• The increase in the population of invasive species caused environmental harm to native species.
• Many parts of the country have experienced an increase in unemployment.
• There has been an increase in demand for two-bedroom apartments.

You will also see the usage "an increase of X percent". For example:

• The report showed increases of between 20 and 30 percent.
• The company had an increase of 10% in its sales. = The company had a 10% increase in sales.

The phrase 'on the increase or on the rise' means "is increasing". Here are example sentences:

• The number of college applications is on the increase. = The number of college applications is increasing.
• Burglaries in the area are on the increase = Burglaries in the area are increasing.

When used as a verb, it means to become or to make something greater in amount, number, value, etc.

Example sentences using the word increase in the verb form:

• Sales increased this year. 
• Skill increases with practice.
• The population is increasing at an unprecedented rate.
• The house increased in value.
• We need to increase productivity. (Used as a transitive verb, meaning make something greater in amount, number, value )
• They've increased the price by 50%.  (Used as a transitive verb, meaning make something greater in amount, number, value )

In the verb form the prepositions “by”, “to” and “with” are often used with the word increase. Take a look at the examples below:

• The budget has increased by more than a third in the last year.
• Last month the reward was increased from £20,000 to £40,000.
• Disability increases with age.

Difference between “increasing” and “increased”

When something is increasing, it means that this thing continues to rise; however, when something has increased, it means that thing has now stopped increasing.

Let’s further look at the difference between “increasing” and “increased” in the following example sentences:

• Lately, scientists have observed “increasing” pollution in the water supply.
• Lately, scientists have observed “increased” pollution in the water supply.

As you just saw, both words can be used in the sentence; but "increasing" would suggest the pollution to the water supply continues to rise, whereas "increased" would suggest it has now stopped.

Now that we have understood the difference between “increased” and “increasing”, I would like you to stop and think about how the words “increased” or “increasing” can be used in the blank space of the following sentence:

• Due to ____ competition, organizations are now operating more efficiently.

Let’s take a look now!

If the competition is still increasing, use increasing. It would mean that the increase is occurring now and is expected to continue. However, if the competition has already increased, and you want to emphasize that fact, use increased.

Let's look at more example sentences using "increasing" and "increased".

• Former agricultural land near large cities has been converted to urban use at an increasing rate.       
• New obesogenic chemicals are being identified at an increasing rate.
• These symptoms are associated with an increased risk of heart disease.

Incubation is the process of incubating eggs; it also refers to the development of the embryo within the egg.

Example sentences are:

• Incubation ensures normal egg development.
• Ambient temperature is commonly thought to influence avian incubation behavior.

Another word that has the same meaning of incubation is brooding. Here are example sentences:

• Fossils indicate that dinosaurs might have brooding behavior.
• Birds have many adaptations to help make brooding successful and ensure a better hatch rate for eggs

An indication is an abstract idea. It is a clue or a suggestion. 

Note:

• an indicator is an object that indicates something.
• An indication is an act of indicating something.

When paraphrasing, you can use "give someone an indication of" or "be an indication of" instead of "indicate". Let's look at the following example:

• The drastic decline in the numbers of amphibians worldwide indicates the global pollution of water and air.

Can be paraphrased to 

• The drastic decline in the numbers of amphibians worldwide gives scientists an indication of the global pollution of water and air.

or 

• The drastic decline in the numbers of amphibians worldwide is an indication of the global pollution of water and air.

Here are more examples:

• Record profits in the retail market is an indication of a boom in the economy = Record profits in the retail market indicates a boom in the economy.
• An increase in crime is an indication of a decline in moral standards. = An increase in crime indicates a decline in moral standards.

​"Indicator" is a thing that indicates the state or level of something. An indicator indicates something or gives an indication of something. 

Note:

• An indicator is an object that indicates something.
• An indication is an act of indicating something. An indication is an abstract idea.

Let's look at the following example to get a better idea of how to use the word "indicator".

The drastic decline in the numbers of amphibians worldwide indicates the global pollution of water and air (= The drastic decline in the numbers of amphibians worldwide is an indication of the global pollution of water and air.)

From the above sentence, we can say that

Calculating the number amphibians worldwide is used as an indicator of global pollution of water and air.

Here are example sentences using the word "indicator":

• Nitrogen oxides are used by scientists as an indicator of economic activity and of the effectiveness of pollution-control measures. 
• Gold prices are often seen as an indicator of inflation.
• Calculating the number amphibians worldwide is used as an indicator of global pollution of water and air.
• The stock market is seen as a leading indicator of economic growth.

You might hear a lot from newscasters about "economic indicators." These are figures, such as the rate of unemployment or inflation that indicate where we're headed economically. Here is an example sentence:

• Economic indicators suggest that prices will go up

Indigenous is a word that can describe a plant, animal or person that is native to an area. Indigenous, aboriginal and native are all synonyms. The phrase "be indigenous to" is often used. For example:

• This delicious berry is indigenous to South Africa.  

• Rather than wandering aimlessly, indigenous peoples of North America tended to follow annual migratory patterns, often driven by the seasonal availability of their primary food sources. 

• Are there any species of frog indigenous to the area? 

• So who are the indigenous people of this land? 

The word "indispensable" is a strong adjective for something that you couldn't do without. For example, if you have asthma and you're packing for summer vacation, your inhaler is indispensable. The word dispensable means something you can go without, so indispensable is something you absolutely cannot go without. Used simply, “Food is indispensable to humans.” The phrase "be indispensable to" is often used.

Example sentences with the word indispensable:

• She is an indispensable (meaning essential) part of the team.
• Water is indispensable to life.
• To most teenagers, their mobile phones are indispensable to their happiness

Definition: (Of an amount or supply of something) unable to be used up because existing in abundance

Example sentences:

• Their say-no-to-drugs mantra affirmed that New York at least has an inexhaustible supply of high energy.

Definition: the early stage of growth or development

Example sentences:

• How much they would lose or gain is a matter of speculation because the legislation is still in its infancy.
• The technology is in its infancy, and changing consumer behavior is half the work.

The adjective "infertile" describes

• land that cannot produce a large number of good quality crops
• animals or plants are not able to produce (a lot of) young or fruit

Example sentences:

• Volcanic soil is often fertile.
• The infertile soils are suitable only for grazing.
• Much of the soil in our nation has become infertile due to the overuse of pesticides, herbicides, and chemical fertilizers.
• It has been estimated that one in eight couples is infertile.

Definition: Capable of being filled with air

Example sentences:

• For 18 months they lived with mattresses on the bedroom floors, a telly, inflatable armchairs and their games consoles.

Influence in the noun form means the power to change or affect, move someone or something. For example:

• Recent years have seen a decline in the company's influence within the industry.

There are many other verbs which can be used together with the word influence. For instance, you can “have an influence on/over/upon sth”, “gain influence”, and "use/wield/exert influence".

"Exert/wield influence" means to use influence, authority, or power in order to affect or achieve something.

Note: If you wield a tool or a weapon, you handle it effectively. Picture a knight wielding a sword. You don't just have to wield something physical; you can also wield or exert influence/power/authority. 

Okay! Here are examples :

• She claims that her personal problems had no/little influence upon her decision to resign.
• His health problems may have had some influence on his decision.
• Her parents still have a great deal of influence over her.
• Her ideas have gradually gained influence in the company.
• He exerted/wielded his influence to reform the company's policies.
• A well-funded national organization would be able to exert/wield more influence in Parliament.
• Common in ancient cultures, the sovereign wielded much power and influence over the people

Let’s look at another phrase "under the influence". It means affected by alcohol.  Here is an example sentence:

• He was arrested for driving under the influence.​

Influence in the verb form means to affect or change (someone or something) in an indirect but usually important way: to have an influence on (someone or something).

Example sentences:

• I was deeply/greatly influenced by my parents.
• Nowadays children are greatly influenced by the sportsperson they see on the television
• No one knows how this decision will influence the outcome of the election.

To inform is to tell someone news, pass on wisdom, leak gossip, or give instruction. For example,

• I inform you of the situation.

Pay attention to the preposition “of. The pattern is ‘inform someone of something’.

Another word that is similar to the word ‘inform’ is ‘impart’. To impart knowledge to is to pass on knowledge to someone. For example,

• Teachers impart knowledge to their students

When you're informed, you have all the information or knowledge that you need. For example,

• Informed students are more engaged and excited about their classes, and of course, they do better on tests.

Another common use of informed is “an informed decision”.

When you make a decision after learning about your options and giving the matter careful thought, that decision is called an informed decision. For example, you can say

• There are many advantages to making an informed decision.

Definition: not many times; almost never

Example sentences:

• Tornadoes occur infrequently in the eastern part of the United States.
• Cold storage refers to low cost storage of information that is expected to be accessed infrequently, such as archives of user search histories.

Ingenuity is the ability to think creatively about a situation or to solve problems in a clever way. If you want to build a boat out of toothpicks and yarn, you’ll need a lot of ingenuity.Ingenuity is all about imagination, and an imaginative mind knows that every obstacle can be overcome with a little ingenuity. 

Example sentences:

• She showed amazing ingenuity in finding ways to cut costs.
• It will take considerable/much/some ingenuity to fix these problems.
• Inspecting the nest may require some ingenuity.

To inhabit is to live in a place to have a home in a place. Here are example sentences:

• Several hundred species of birds inhabit the island.
• This part of the country is inhabited by native tribes.
• The island is no longer inhabited. [=no people live there]

An inhabitant is a person who inhabits (or lives) in a particular place..

Here is an example sentence:

• The Adena peoples are the first known inhabitants in the modern-day United States territory.

Definition: Hinder, restrain, or prevent

Example sentences:

• Public provision of social security assistance could become less important if governments remove policies inhibiting innovation or restraining growth.

If you initiate something, you start it. Here are example sentences:

• They wanted to initiate a discussion on economics.
• The trip was initiated by the manager of the community center. 
• If you wanted to initiate a change in your workplace, you may request a meeting with your boss

If you initiate someone into something, you introduce them to a particular skill or type of knowledge and teach them about it. Here are example sentences :

• He initiated her into the study of other cultures.

Definition: something newly introduced; ahead of the times

Example sentences:

• The innovative tool promises to clarify the still-murky details of the initial infection process and may help guide drug, vaccine, and cure research in people.

Definition: beyond normal limits

Example sentences:

• The average adult human brain only weighs about three pounds, but it consumes an inordinate amount of glucose, oxygen, and blood flow.

The noun "inscription" means writing or short message. An example in a sentence:

• The inscription on the museum door was thought-provoking.

Inshore is an adjective, describing something is in the sea but close to the land. If something is inshore, it is in the sea but quite close to the land. If something moves inshore, it moves from the sea towards the land. An example in a sentence:

• In the Northeast, many adult fish reproduce out on the continental shelf, but their young develop to adulthood in inshore estuaries.

When you have an insight, you have a feeling or emotion or thought that helps you to know something essential about a person or thing.Insight isn't based on hard facts or evidence. And it doesn't have anything to do with using your senses such as sight or smell. When you gain insight, you are using your intuition or sixth sense.  

Insight means the ability to understand people and situations in a very clear way.  In this case, it is uncountable. For example:

• He is a leader of great insight.

Insight can also mean an understanding of what something is like. The following two patterns are often used

• Someone gains insight(s) into something
• Sth gives someone insight(s) into something

In this case, insight can be used as countable and uncountable. Either form could be used depending on the context, assumptions, hopes, etc... Let's look at the following examples

• The book gives us fascinating insights into life in Mexico.
• I hope you have gained some insight into the difficulties we face.

In the first sentence, Mexican life is assumed to be complex. It is assumed that there are many moments (while reading) in which the reader will say, "AH! I understand!".

Each of those moments is //an insight// (event: a moment of understanding). Each moment gives us //some insight// (some knowledge, uncountable) into Mexican life.

Do you see the difference here? The book is giving us discrete //moments//. Each moment is //an insight// into Mexican life. Therefore the book is giving us many insights -- plural insights. Each moment adds to our general knowledge of, our (uncountable) insight into, Mexican life.

---------------

Consider the second sentence: "I hope you have gained some insight into the difficulties we face."

It is not describing any kind of "moment", instead it is like saying, "I hope you gained some knowledge".

You could rewrite it to use a countable insight as follows:

• I hope this meeting has given you an insight into the difficulties we face (singular event -> singular insight)
• I hope these meetings have given you many insights into the difficulties we face. (plural meetings -> plural insights)

Definition: of little importance or influence or power; of minor status

Example sentences:

• If the company can get over entrenched competition and some not insignificant cultural barriers, there’s no reason why America couldn’t get hooked on Line.

Definition: Careful examination or scrutiny

Example sentences:

• Such inspections are conducted only on the basis of complaints and to verify discrepancies.
• We carry out regular safety inspections

The adjective instantaneous describes something that is happening right now, without delay. 

A synonym for “instantaneous” is “instant.” or "immediate". However, most English speakers would say that something that is instantaneous happens even more quickly than something that is instant.  In addition, instantaneous is much less frequently used than instant, and it is a more formal word. It is used mostly to describe things that happen in concrete, academic, or scientific contexts.

Example sentences using the word instantaneous:

• We got an almost instantaneous response from the company.
• In today's society, the technology we carry in our pockets means people often expect an instantaneous or immediate response to emails and text messages
• Computers have created a system for easy and instantaneous communication.
• While personal cell phones have facilitated instantaneous connections with people, texting is a cause of underdeveloped communication skills in children.
• Through email or various video chat websites, people can send instantaneous messages or speak as if in person.

To instigate is to provoke, or stir up, but if often used in a negative way. Many times when you instigate something, it may not end up how you planned. 

Example sentences using instigate:

• There has been an increase in the amount of violence instigated by gangs.
• She blamed him for instigating (meaning starting) the argument.​
• The government has instigated an investigation into the cause of the accident.

The adjective instinctive describes something you do without thinking about it. If you have an instinctive desire to help animals, you might automatically stop your car to pick up every stray dog you see. Adults also have instinctive reflexes — like yawning, or the reflex that makes you kick your leg when the doctor hits your knee with a rubber mallet. 

Something that is instinctive occurs naturally, like the way babies know how to cry as soon as they're born. 

Things that are instinctive to you are part of your personality. Every day, you may walk to the coffee machine before you realize what you are doing, but having a morning coffee is an instinctive part of your morning routine.

An instrument is a device that that requires skill for proper use, but is normally referring to something that makes music. Pianos, flutes and violins are all instruments.

Definition: the room was heavily insulated against all outside noise

Example sentences:

• With hot water heating systems, the diameter of the piping remains constant, the slope is irrelevant, and all lines are insulated to prevent heat loss.

The verb “insure” means to buy insurance for (something, such as property or health). It can also be similar in meaning to ensure - to make something sure, certain or safe. The word iinsure" can also mean to provide someone with insurance. For example; she had difficulty finding a company that would insure her.

The word is often used with an object as seen in the examples below:

• He insured the boat.
• We insured our house against fire and flood damage
• I found a company that will insure my car for less than I've been paying.
• This policy will insure your car against theft.

The phrasal verb insure against is commonly used when talking about insure. Let’s look at the phrase in detail below:

• Insure against (something)
• Insure (someone) against (something)

The first example “insure against (something)” means to make (something bad) less likely to happen usually by planning and preparing.

Example sentences:

• Doctors recommend exercising to insure against health problems.
• Despite all of our planning, we can't insure against bad weather.

Something that is integral is very important or necessary. If you are an integral part of the team, it means that the team cannot function without you. A synonym for integral would be essential.

You will see the collocation "an integral part" a lot.

Example sentences of the word integral:

• She had become an integral part of the team.
• Some would argue that sport is an integral part of the school curriculum.
• Computers are an integral part of life and so is computer education!

The phrase “be integral to” is often used.  Look at the following examples below:

• His character is integral to the story.
• Luck was integral to our success.

Definition: with intention; in an intentional manner

Example sentences:

• Users should not put up with major companies that are intentionally creating a poor user experience by keeping these practices alive.
• The researchers found that ivory is often shipped from countries different to where it was poached, and traffickers intentionally try to mislead authorities.

The adjective internal describes something on the inside. If you're tempted by the second piece of cake, you may have an internal battle with yourself over whether you should eat the cake or not. You might have an internal struggle with whether or not you should go on the vacation because you are a little short of cash.

Internal can also describe something that takes place within a country or a group.You may have to write internal reports for your boss––reports that aren't supposed to be seen outside the company. 

Example sentences using "internal" as a representation of locating on the inside:

• The internal structure of the planet
• The theory has some internal inconsistencies

Countries and organizations have internal affairs. An example sentence of each is shown below:

• The office of internal revenue
• The new policy was spelled out in an internal memo

Interplay is a reciprocal action and reaction. For example, an action could be you had a hair in your mouth, and a reaction would be to spit.

• The interplay of the employees and customers is what makes our business so successful.

Definition: Diversify (a thing or things) with other things at intervals:

Example sentences:

• Now, during the US war on Iraq, news from the frontlines is seamlessly interspersed with news from the stock markets.

The Intertidal Zone is where the land meets the sea. It is the area between high tide and low tide.

Definition: Unable to be endured

Example sentences:

• As the true horror of the situation emerges, that sense of duty becomes an intolerable pressure.

Definition: Very complicated or detailed

Example sentences:

• I seem to remember my dreams in unusually intricate detail and twice as often as most people. The intricate detail and structure of this miniscule world is breathtaking.

Intriguing things or people arouse curiosity and have an indescribable draw.  Synonyms for intriguing are captivating, riveting, and titillating.

Example sentences using intriguing

• The book was so intriguing, I couldn’t put it down!
• If you find the night sky intriguing and enjoy pondering the limitlessness of the universe, you should consider becoming an astronomer.
• He has an intriguing personality
• This intriguing book is both thoughtful and informative

Definition: A thing that intrudes; The action or process of forcing a body of igneous rock between or through existing formations, without reaching the surface

Example sentences:

• Overthrusting, volcanism, and plutonic igneous intrusion were identified as originating above the subduction zone where one plate is forced beneath the edge of its neighbour.
• Traffic generates noise and pollution, and is an intrusion for many areas.

Definition: fill or cover completely, usually with water

Example sentences:

• The radio stations were inundated with reports of a severe traffic accident.
• Practically every Internet user is inundated with spam or virus-riddled messages daily.

Definition: In every case or on every occasion; always

Example sentences:

• Depression moods lead, almost invariably, to accidents. But, when they occur, our mood changes again, since the accident shows we can draw the world in our wake, and that we still retain some degree of power even when our spirits are low.

Definition: An animal lacking a backbone, such as an arthropod, mollusk, annelid, coelenterate, etc. The invertebrates constitute an artificial division of the animal kingdom, comprising 95 percent of animal species and about 30 different phyla

Example sentences:

• During the breeding season they eat mostly insects and other invertebrates.

Definition: done without will or conscious control.

Example sentences:

• Dreams are nothing but the successions of images , ideas, emotions , and sensations that occur involuntarily in the mind during certain stages of sleep

Definition: The layer of the earth’s atmosphere which contains a high concentration of ions and free electrons and is able to reflect radio waves. It lies above the mesosphere and extends from about 80 to 1,000 km above the earth’s surface.

Example sentences:

• The ionosphere reflects neither FM radio nor broadcast television, itself a part of the radio spectrum.

Definition: Occurring at uneven or varying rates or intervals

Example sentences:

• Income can be withdrawn at irregular intervals to suit individual circumstances as long as the payments are in accordance with the above limits.
• The rhythm is irregular, and the rate can vary or become sinus bradycardia because of the long pauses.

Irrigation is the watering of the land to make it ready for farming. People often set up irrigation systems, such as sprinklers, to prepare the land for crops. It can mean to supply dry land with water, even in the form of ditches. Here are example sentences:

• The crops failed because there wasn’t a proper irrigation system.
• Dryland farming is the practice cultivating crops without irrigation. 
• Unsustainable practices in irrigation and production may lead to soil degradation.
• California’s primary agricultural land is in semiarid or arid zones where precipitation is highly seasonal and often nil during the growing season. Therefore, nearly all food and feed crop production depend on irrigation.