noun
1.
grave disorder of mind that impairs one's capacity to function safely or normally in society
his insanity required confinement in a mental institution
Synonyms: aberration, alienation, derangement, distraction, insaneness, lunacy, madness, psychopathy, unbalance
Related Word: acromania; delirium, frenzy, hysteria; delusion, hallucination, illusion; irrationality, unreasonableness; dotage
Contrasted words: judiciousness, sageness, sensibility, wiseness; rationality, reasonableness; healthiness, soundness, wholesomeness
Antonyms: saneness, sanity
2.
Synonyms: foolishness , absurdity, craziness, dottiness, folly, inanity, preposterousness, senselessness, silliness, witlessness
Related Word: asininity, fatuousness, stupidity; impracticality