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.
verb (used without object)
- to grow or become worse; lessen.
- Archaic. impairment.
- (tr) to reduce or weaken in strength, quality, etchis hearing was impaired by an accident
late 14c., earlier ampayre, apeyre (c.1300), from Old French empeirier (Modern French empirer), from Vulgar Latin *impeiorare “make worse,” from assimilated form of in- “into, in” (see in- (2)) + Late Latin peiorare “make worse” (see pejorative). In reference to driving under the influence of alcohol, first recorded 1951 in Canadian English. Related: Impaired; impairing.