English Reference
adjective · noun

impaired

adj. · n.
US /ˌɪmˈpɛɹd/ UK /ɪmpˈeəd/ im·paired

  1. 01 B2 Upper Intermediate Formal

    adj.damaged or weakened so that it does not work perfectly.

    adj.rendered less effective, weakened, or damaged in function or quality.

    Simple

    His vision was impaired after the accident, so he had to wear glasses.

    In context

    The patient's cognitive functions were significantly impaired by the stroke, necessitating a long-term rehabilitation plan focused on speech and memory.

    Usage

    Often used in medical or technical contexts to describe senses like hearing or vision.

  2. 02 C1 Advanced FormalTechnical Law

    adj.not able to think or act clearly because of alcohol or drugs.

    adj.functioning at a diminished capacity due to the consumption of alcohol or controlled substances.

    Simple

    The police stopped the driver because he appeared to be impaired.

    In context

    Operating heavy machinery while impaired by prescription medication is strictly prohibited under the current safety guidelines.

    Teacher's tip

    This is a formal and legal way to say someone is drunk or high; it is the standard term used in police reports and courtrooms.

    intoxicateddrunkinebriated
  3. 03 C2 Proficiency American EnglishTechnical Law

    n.a crime where someone drives a car while they are drunk or high.

    n.a criminal offence involving the operation of a motor vehicle while under the influence of intoxicants.

    Simple

    He lost his license after being charged with an impaired.

    In context

    The defendant faced a mandatory minimum sentence after his second impaired in three years.

    Usage

    Used as a countable noun primarily in North American legal contexts.

    DUIdrunk driving

Performance was impaired when checked 15 minutes, four hours, eight hours and 24 hours later.

BBC News· 15 Aug 2026

A four-hour delay was corrected 50% faster in mice, and six-hour shifts in macaques were reduced by about one day, without impaired sleep or major toxicity.

Phys.org· 14 Aug 2026
This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated