- not sane; not of sound mind; mentally deranged.
- of, relating to, or characteristic of a person who is mentally deranged: insane actions; an insane asylum.
- utterly senseless: an insane plan.
- mentally deranged; crazy; of unsound mind
- (as collective noun; preceded by the)the insane
- characteristic of a person of unsound mindan insane stare
- irresponsible; very foolish; stupid
1550s, from Latin insanus “mad, insane; outrageous, excessive, extravagant,” from in- “not” (see in- (1)) + sanus “well, healthy, sane” (see sane). Originally only of persons; of actions, from 1842. Cf. lunatic; and Italian pazzo “insane,” originally a euphemism, from Latin patiens “suffering.” German verrückt, literally past participle of verrücken “to displace,” “applied to the brain as to a clock that is ‘out of order’ ” [Buck]. The noun meaning “insane person” is attested from 1786.
- Of, exhibiting, or afflicted with insanity.