Definition of insanity noun from the Oxford Advanced Learner's Dictionary



    BrE BrE//ɪnˈsænəti//
    ; NAmE NAmE//ɪnˈsænəti//
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  1. 1the state of being insane synonym madness He was found not guilty, by reason of insanity. opposite sanity
  2. 2actions that are very stupid and possibly dangerous synonym madness, lunacy It would be sheer insanity to attempt the trip in such bad weather.
  3. Word Originlate 16th cent.: from Latin insanitas, from insanus, from in- ‘not’ + sanus ‘healthy’.Extra examples Congress has one option to stop this insanity. Hamlet feigns insanity to disguise his bloody motive. He was found not guilty by reason of insanity. His lawyer got him off on an insanity plea.
See the Oxford Advanced American Dictionary entry: insanity