Other forms: impaired, impairs, impairing
To impair something is to weaken or damage an ability. Sight, hearing, judgement, memory.
The word is formal and medical, and it always attaches to a faculty rather than an object, so you impair judgement but you damage a car. Drink-driving law uses it precisely, since driving while impaired is an offence in itself. The adjective impaired is the standard respectful term in visually impaired and hearing impaired. The noun impairment names the condition, and unimpaired means working perfectly.
1verbimpairTo weaken or damage a faculty or ability.
“Lack of sleep impairs concentration.”
To impair is to make worse. Old French empoirier goes back to Latin peiōrō, to worsen, from peior, worse, the comparative of malus, bad, so impairment is not damage exactly but a turn for the worse.
Latin
peiōrō — worsen
la-eme
impeioro
Old French
empoirier
Middle English
impairen
English, today
impair
Built from
From Middle English impairen, empeiren, from Old French empoirier, from la-eme impeioro, from in- + Latin peiōrō (“worsen”), from peior (“worse”), comparative of malus (“bad”).
Etymology from Wiktionary, CC BY-SA