impairs

Impair is a verb meaning to weaken, damage, or reduce the function, value, or quality of something. Impairs is the third-person singular present tense form: “The fault impairs the device’s performance.” The word is transitive and takes a direct object, as in “smoke impairs breathing” or “excessive load impairs structural integrity.” It can describe physical effects, sensory or cognitive decline, or diminishing performance, safety, or reliability.

The related noun impairment denotes a reduction in function or ability (for example, cognitive impairment or impairment of assets). Impairing is the present participle, and impaired is the past participle or adjective, as in “impaired vision” or “impaired judgment.”

Origin and usage: The verb dates to Middle English, from Old French empairer, meaning to weaken or lessen. In modern formal writing, impair is common in medical, legal, technical, and policy contexts, where precision about the degree or cause of weakening matters.

Examples illustrate the range of use: “Exposure to secondhand smoke impairs respiratory health.” “A data breach can impair customer trust.” “Asset impairment requires a write-down to reflect reduced value.”

See also impairment.