OXFORD DICTIONARY

screwball, n. & adj. US sl.
--n. a crazy or eccentric person.
--adj. crazy.

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THESAURUS

screwball

abnormal, alien, aliene, anomalous, balmy, bananas, barmy, bats, batty, beany, bedlamite, bonkers, borderline case, bowl, buggy, bughouse, bugs, case, cast, change of pace, change-up, character, chuck, chunk, crackbrain, crackers, crackpot, crank, crankish, cranky, crotchety, cuckoo, curve, daffy, dement, demoniac, deviant, deviative, different, ding-a-ling, dippy, divergent, dotty, downcurve, eccentric, energumen, erratic, exceptional, fanatic, fastball, fey, flake, flaky, fling, flip, flipped, forward pass, fou, freak, freaked-out, freakish, fruitcakey, fruity, funny, gaga, goofy, harebrain, haywire, heave, hermit, hobo, hurl, idiocratic, idiosyncratic, idiot, incurve, irregular, just plain nuts, kinky, knuckleball, kook, kooky, lateral, lateral pass, lob, lone wolf, loner, loon, loony, loopy, lunatic, madman, maggoty, maniac, maverick, meshuggenah, natural, noncompos, nonconformist, nut, nuts, nutty, odd, odd fellow, oddball, oddity, off the hinges, off the track, off the wall, original, outcurve, outsider, pariah, pass, peculiar, peg, phrenetic, pitch, potty, put, queer, queer duck, queer fish, queer specimen, quirky, rara avis, raving lunatic, recluse, round the bend, screwballs, screwy, serve, service, shot-put, shy, singular, sinker, slaphappy, slider, sling, solitary, spitball, spitter, strange, strange duck, throw, toss, tramp, twisted, type, unconventional, unnatural, upcurve, wacky, weirdo, whimsical, zealot

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