insane

in-sane · adjective

imported

Definitions

adjective

  1. 1.

    (dated, medical/legal) In a state of mental illness; not of sound mind.

  2. 2.

    (informal) Extremely foolish, irrational, or absurd.

  3. 3.

    (informal) Extremely impressive, intense, or remarkable.

Phrases & expressions

  • •
    insane asylum — (dated) a hospital for the mentally ill
  • •
    drive someone insane — to annoy or frustrate someone greatly
  • •
    the insane — (noun) mentally ill people (dated usage)

Related words

Antonyms: rational, sane, sensible
See also: crazy, insanity, mad
Synonyms: crazy, deranged, mad

Etymology

From Latin insanus ("unhealthy, mad"), from in- ("not") + sanus ("healthy, sane"). Entered English in the 16th century.