# impair

/ˌɪmˈpɛɹ/ (US) · /ɪmpˈeə/ (UK) · CEFR C1 · Verb

Source: https://englishreference.com/word/impair
Updated: 2026-05-19

## Definition

to make something less effective or worse. You use this when a person or thing is not working as well as it should.

For teachers: to reduce the effectiveness, quality, or value of something; to cause a loss of physical or mental ability.

## Examples

- The heavy rain began to impair the driver's vision.
- The new law aims to prevent substances that might impair a pilot's judgment from being used before a flight.
- While the initial damage was minor, the constant exposure to saltwater eventually began to impair the structural integrity of the ancient stone walls.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.