INSANITY

n. 1 madness, lunacy, mental illness or disorder, dementia (praecox), psychosis, schizophrenia, (mental) derangement, mania; psychoneurosis, neurosis Because of the plea of temporary insanity he never stood trial for the murders 2 folly, foolishness, stupidity, idiocy, imbecility, lunacy, absurdity, fatuity, fatuousness, nonsense, senselessness, irresponsibility, irrationality, inanity: What insanity it was to think I could win the lottery!