Synonyms and Antonyms of insane
- Only an insane person would intentionally jump off a skyscraper.
balmy, bats, batty, bedlam, bonkers, brainsick, certifiable, crackbrained, cracked, crackpot, crazed, crazy, cuckoo, daffy, daft, demented, deranged, gaga, kooky (also kookie), loco [slang], loony (also looney), lunatic, mad, maniacal (also maniac), mental, non compos mentis, nuts, nutty, psychotic, screwy, unbalanced, unhinged, unsound, wacky (also whacky)
around the bend, off one's gourd, off one's head, off one's rocker, out of one's head (or mind)
- a completely insane plan to build a ball field in the middle of nowhere
off the wall [slang]
- an insane idea to blow all of their savings on lottery tickets
absurd, asinine, balmy, brainless, cockeyed, crackpot, crazy, cuckoo, daffy, daft, dippy, dotty, fatuous, featherheaded, fool, foolish, half-baked, half-witted, harebrained, inept, jerky, kooky (also kookie), loony (also looney), lunatic, lunkheaded, mad, nonsensical, nutty, preposterous, sappy, screwball, senseless, silly, simpleminded, stupid, tomfool, unwise, wacky (also whacky), weak-minded, witless, zany
airheaded, birdbrained, brain-dead, chowderheaded, chuckleheaded, clueless, dense, dim, dim-witted, doltish, dopey (also dopy), dorky [slang], dull, dumb, dunderheaded, empty-headed, fatuous, feebleminded, idiotic (also idiotical), imbecile (or imbecilic), knuckleheaded, lamebrain (or lamebrained), mindless, moronic, oafish, obtuse, opaque, pinheaded, simple, slow, slow-witted, soft, softheaded, thoughtless, thick, thickheaded, unintelligent, vacuous, witless
out to lunch
- wanted an insane amount of money to paint our house
a bit much, over the top
Seen and Heard
What made you want to look up insane? Please tell us where you read or heard it (including the quote, if possible).