What does impair mean?
To impair something is to weaken it, damage it, or reduce how effectively it works. The word is especially common when describing a loss of physical or mental function caused by illness, injury, age, or another condition: impaired hearing, impaired memory, and impaired mobility are typical examples. It can also refer to lessening the value, quality, or effectiveness of something, as in impairing trust or interfering with a person's ability to work. “Impair” is more formal than casual alternatives such as “damage” or “weaken,” and it is particularly frequent in medical and legal writing. It carries a distinctly negative implication: something previously effective, healthy, or sound has been reduced below its former condition, although it does not necessarily mean that the affected thing has been destroyed completely. The related noun “impairment” denotes the resulting weakness or limitation.
verbTo weaken or damage something, especially a person's health, faculties, abilities, or an object's condition or performance. It can also mean to diminish the value or effectiveness of something.
- To weaken or damage a person's health, senses, faculties, or physical condition.
- To diminish the ability, effectiveness, value, or performance of a person, thing, or process.
"A lack of sleep can impair concentration and impair one's ability to make sound decisions."
"The injury permanently impaired his hearing."
"Misleading advertising can impair consumers' ability to make informed choices."
The word began with the idea of making things unequal: its Latin roots combine a prefix meaning “not” with one meaning “equal.”
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does impair come from?
The word entered English from Old French, which drew on Latin forms built from the prefix meaning “not” and a root meaning “equal.” Its original sense was “to make unequal,” which developed into the modern meanings of weakening, damaging, or diminishing. The same root underlies words such as “impartial,” “partial,” and “parity,” all connected with equality or equal treatment.
Related word forms
How impair is actually used
The word is formal and especially common in medical, legal, and technical contexts. In medical usage, it describes a significant loss or reduction of normal function; in legal usage, it may refer to a person's capacity being reduced or made less effective.
Easily confused with impair
To impair is to weaken or damage a function or condition, whereas to imprison is to confine someone in prison.
Impair means to weaken or damage; it does not mean to compare with something, which is the meaning of compare.