Synonyms for Crazy:

adj.

absurd (adjective)
self-contradictory, foolish, outlandish, fallacious, implausible, anachronistic, inane, bizarre, meaningless, loony, idiotic, preposterous, eccentric, ridiculous, invalid, ludicrous, paradoxical, absurd, nonsensical, impossible, contradictory, inconsistent, silly, irrational, incongruous, senseless, laughable, illogical, farcical.
crazed (adjective)
berserk.
deranged (adjective)
nutty.
foolish (adjective)
tomfool, asinine, doltish, loony, dim-witted, nonsensical, meat-headed, half-witted, blithering, lame-brained, inane, dopey, foolish, nitwit, cockeyed, dippy, bone-headed, idiotic, blockheaded, ignorant, chuckle-headed, absurd, crackpot, brainless, imbecilic, moronic, zany, cretinous, dumb, dotty, goofy, knuckle-headed.
infatuated, in love (adjective)
enamored, ardent, keen, zealous, hysterical, smitten.
insane (adjective)
hysterical, schizoid, delirious, psychotic, brainsick, blithering, feverish, berserk, batty, deranged, mad, lunatic, babbling, insane, unbalanced, demented, maniacal, psycho, moonstruck, gaga, kooky, frenzied, bananas, irrational, Crack-brained, brain-sick, nutty, neurotic.
lunatic (adjective)
lunatic, nutty, psychotic, Fiendish, neurotic, kooky, mad, crackpot.
mentally strange (adjective)
erratic, batty, demented, psycho, dippy, cuckoo, delirious, silly, kooky, maniacal, mad, unbalanced, nutty, berserk, screwy, touched, screwball, insane, moonstruck, unhinged, deranged, idiotic, lunatic.
nonconforming (adjective)
eccentric, outlandish, mismatch, un-ordinary, untypical, extraordinary, incompatible, odd, curious, peculiar, different, unfamiliar, anomalous, abnormal, oddball, freakish, idiosyncratic, novel, improper, atypical, erratic, deviant, oddity, bizarre, deranged, unconventional, fey, irregular, singular, divergent, unique, unusual, strange, exceptional, misfit, quirky, aberrant, nonconforming, out of the ordinary, uncustomary, funny, incongruous, uncommon, crosspatch, off, inconsistent.
ridiculous (adjective)
outrageous, ludicrous, ridiculous, bizarre, comical, absurd, nonsensical, dubious, silly, poppycock, foolish, farcical, grotesque, preposterous, eccentric, weird, oddball, curious, laughable, incredible, outlandish.
screwy (adjective)
screwy.
unrealistic, fantastic (adjective)
goofy, cockeyed, foolish, ludicrous, nonsensical, inane, eccentric, preposterous, ridiculous, loony, bizarre, peculiar, odd, half-baked, outrageous, strange, absurd, weird, senseless.

n.

not in your right mind/not right in the head, childish, over-the-top. fervent, rabid, warm, ardent, keen, concern, gung ho, zealous. jerky, tomfool, cockeyed, unearthly, knowledge, ability, dippy, sappy, zany. crazy (noun)
gaga, looney, meshugge, brainsick, strange, unusual, smitten, excited, taken with, unbalanced, in love, meshuga, insane, half-baked, enamored, impractical, loving, weirdo, enthusiastic, demented, unhinged, sick, loony, disturbed, softheaded, soft on, screwball, dotty, mad, infatuated, distracted.
eccentric person (noun)
kook.
lunatic (noun)
kook, fiend, madman, crank, maniac, psychopath, nut.
person (noun)
weirdo, looney, loony.

Other synonyms:

jerky, over-the-top, loon, cuckoo, gung ho, Daffy, dippy, ding-a-ling, dingbat, non compos mentis, mentally ill, bananas. zealous, distraught, warm. disordered, childish, touched, unsound, rabid, zany, fervent, ardent, moonstruck, sappy. keen, unearthly. wrong. odd
screwy.

Usage examples for crazy

  1. Sometimes he isn't so crazy – The Wrong Twin by Harry Leon Wilson
  2. Are you gone crazy – Footsteps of Fate by Louis Couperus
  3. We both must be going crazy to go on as we do. – Undertow by Kathleen Norris