Synonyms

impair

¹ American

[im-pair] / ɪmˈpɛər /

verb (used with object)

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

verb (used without object)

to grow or become worse; lessen.

noun

Archaic. impairment.

impair ² American

[an-per] / ɛ̃ˈpɛr /

adjective

French.

noting any odd number, especially in roulette.

impair British

/ ɪmˈpɛə /

verb

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

his hearing was impaired by an accident

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See injure.

Other Word Forms

Derived Forms

Inflected Forms

Participles

Conjugated Forms

Present

Past

Future

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”; cf. 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.”

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Vocabulary lists containing impair

List 6

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Essential English Vocabulary, List 5

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United States v. Nixon (1974)

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Dementia is an umbrella term for debilitating symptoms that can result in memory loss and impair movement and daily life.

From Barron's • Jun. 15, 2026

Remember, if you’re forced to sell depressed assets to fund living expenses, you permanently impair the portfolio.

From MarketWatch • Jun. 2, 2026

“Inadequate nutrition, particularly vitamin A deficiency, can impair the lining of the digestive tract, predisposing birds to inflammation and secondary illness.”

From Los Angeles Times • Apr. 20, 2026

She referenced research published earlier this month, which highlighted a "bi-directional relationship" in which mental health problems that "impair self-care behaviours" could cause diabetes complications, and in turn "further impair mental health".

From BBC • Apr. 17, 2026

In the earlier discussion, however, I was referring to things that impair our ability to solve problems.

From "Blink" by Malcolm Gladwell

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023