impair

¹ American  

[im-pair] / ɪmˈpɛər /

verb (used with object)

1. to make or cause to become worse; diminish in ability, value, excellence, etc.; weaken or damage.

   to impair one's health;

   to impair negotiations.

   Antonyms:

   repair

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verb (used without object)

1. to grow or become worse; lessen.

noun

1. Archaic. impairment.

impair ² American  

[an-per] / ɛ̃ˈpɛr /

adjective

French.

1. noting any odd number, especially in roulette.

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impair British  

/ ɪmˈpɛə /

verb

1. (tr) to reduce or weaken in strength, quality, etc

   his hearing was impaired by an accident

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Related Words

See injure.

Other Word Forms

• impairable adjective
• impairer noun
• impairment noun
• nonimpairment noun
• preimpairment noun
• self-impairable adjective
• self-impairing adjective
• unimpairable adjective

Etymology

Origin of impair¹

First recorded in 1250–1300; Middle English empairen, empeiren “to make worse,” from Middle French empeirer, from em- im- ¹ + peirer “to make worse” (from Late Latin pējōrāre, verb derivative of Latin pējor “worse”; pejoration )

Origin of impair²

First recorded in 1820–30; from French: literally, “odd,” from Latin impār “odd, unequal”; equivalent to im- ² ( def. ) + pair ² ( def. )

Explanation

If you make bad decisions in the morning after drinking coffee, you might conclude that caffeine tends to impair your judgment. When you impair something, you damage it or make it work poorly. The root of the verb impair traces back to the Latin word pejorare, meaning “to make worse,” and that’s still what happens if you impair something. Whether it’s communication, visibility, or your marriage prospects, if you impair it, you make it worse. The word can be used for situations that describe something that has deteriorated, such as “Snow continued to impair driving conditions.”

Example Sentences

Previous research had already shown that PAM variants are more common in people with diabetes and can impair insulin release from the pancreas.

From Science Daily • Apr. 12, 2026

The committee’s authority is limited to very uncommon circumstances in which there are no “reasonable and prudent alternatives” that would avoid jeopardizing a listed species or impair a species’ critical habitat.

From Salon • Apr. 7, 2026

“Supply chain disruptions could increase inflation, tighten credit conditions, and impair earnings, particularly for energy-intensive industries,” they say.

From The Wall Street Journal • Mar. 26, 2026

The centre's chief executive, Jackie Rodriguez, told the BBC that dyslexia does not impair a person's intelligence, judgement or ability to lead.

From BBC • Mar. 16, 2026

All rulers of all ages have tried to impose a false view of the world upon their followers, but they could not afford to encourage any illusion that tended to impair military efficiency.

From "1984" by George Orwell

Related Words

• blunt
• damage
• debilitate
• decrease
• destroy
• diminish
• hurt
• lessen
• mar
• prejudice
• reduce
• spoil
• tarnish
• undermine
• weaken
• worsen