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

Treating old stem cells with the lysosomal inhibitor increased their blood-forming ability in living animals by more than eightfold, highlighting the powerful regenerative effects of correcting lysosomal dysfunction.

From Science Daily • May 12, 2026

Revolution is running trials on a next-generation RAS inhibitor that could be even more effective, as well as testing daraxonrasib in non-small cell lung cancer.

From The Wall Street Journal • Apr. 19, 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

To achieve this, scientists used JQ1, a small molecule inhibitor originally developed to study cancer and inflammatory diseases.

From Science Daily • Apr. 7, 2026

When horned and hornless individuals are crossed the presence of the inhibitor from one line of ancestry is sufficient to suppress the development of horns in the progeny.

From Being Well-Born An Introduction to Eugenics by Guyer, Michael F.

Related Words

• avoidance