insanity

in-san-i-ty · noun

imported

Definitions

noun

  1. 1.

    (law) A mental state that renders a person not legally responsible for their actions.

  2. 2.

    (dated) The state of being seriously mentally ill.

  3. 3.

    Extreme foolishness or irrationality; actions that seem completely unreasonable.

Phrases & expressions

  • •
    temporary insanity — a legal defense claiming momentary loss of reason
  • •
    insanity defense — pleading not guilty by reason of mental illness
  • •
    the definition of insanity — (attributed to Einstein) doing the same thing repeatedly and expecting different results

Related words

Antonyms: rationality, reason, sanity
See also: insane, madness, sanity
Synonyms: craziness, lunacy, madness

Etymology

From Latin insanitas ("unhealthiness, madness"), from insanus ("not healthy, mad"). Entered English in the 16th century.