inhibitor

American  

[in-hib-i-ter] / ɪnˈhɪb ɪ tər /

Or inhibiter

noun

1. a person or thing that inhibits.

2. Chemistry. a substance that decreases the rate of or stops completely a chemical reaction.

3. any impurity in a mineral that prevents luminescence.

4. Rocketry. an inert antioxidant used with solid propellants to inhibit burning on certain surfaces.

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inhibitor British  

/ ɪnˈhɪbɪtə /

noun

1. Also called: inhibiter.  a person or thing that inhibits

2. Also called: anticatalyst.  a substance that retards or stops a chemical reaction Compare catalyst

3. biochem

   1. a substance that inhibits the action of an enzyme

   2. a substance that inhibits a metabolic or physiological process

      a plant growth inhibitor

4. any impurity in a solid that prevents luminescence

5. an inert substance added to some rocket fuels to inhibit ignition on certain surfaces

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Etymology

Origin of inhibitor

First recorded in 1865–70; inhibit + -or ²

Explanation

An inhibitor is a substance or material that slows down or halts some activity. This word is popular in the chemistry lab, but you might also hear it at a garage. For example, a corrosion inhibitor helps slow down rust. When you feel inhibited, you feel self-conscious and less likely to do things. In chemistry, an inhibitor has the effect of squelching something, shutting it down, or slowing it. For example, in a car engine, antifreeze is an inhibitor — it prevents or slows the formation of ice. Different substances are inhibitors for different reactions and activities. Think of an inhibitor as chemistry's way of saying "Slow down!" or "Stop!"

Example Sentences

Doctors typically then give a checkpoint inhibitor or targeted drug if patients have a particular mutation, but many still continue to show cancer progression.

From The Wall Street Journal • Apr. 21, 2026

J&J also received FDA approval last month for a new IL-23 inhibitor pill, Icotyde, for plaque psoriasis.

From MarketWatch • Apr. 14, 2026

Anktiva, in combination with an immune checkpoint inhibitor, received accelerated approval in Saudi Arabia earlier this year for the treatment of metastatic non-small-cell lung cancer.

From Barron's • Mar. 24, 2026

The researchers believe this inhibitor could represent a broadly applicable strategy for slowing or stopping neurodegenerative diseases such as Alzheimer's and ALS.

From Science Daily • Mar. 23, 2026

Probably we ought to regard the beardless as a bearded wheat in which there is an inhibitor that stops the beard from growing.

From Mendelism Third Edition by Punnett, Reginald Crundall

Related Words

• avoidance