maniac

1 a person judged to be legally or medically insane they should permanently put away the maniac who is responsible for these kidnappings Synonyms bug, crackbrain, crazy, fool, fruitcake, head case, loon, loony, lunatic, nut, nutcase, nutter [British slang], psycho, psychopath, sickie, sicko, wacko (also whacko)Related Words madman, madwoman; abnormal, deviant; manic-depressive, monomaniac, mythomaniac, neurotic, obsessive, obsessive-compulsive, paranoid, psychoneurotic, psychotic, schizo, schizoid, schizophrene, schizophrenic, sociopath; character, codger, crack, crackpot, crank, eccentric, fantastic (also fantastical), flake, kook, oddball, oddity, original, quiz, screwball, tyke (also tike) [chiefly British], weirdo, zany; case, patient

2 a person with a strong and habitual liking for something I'm a maniac for anything flavored with peppermint Synonyms addict, aficionado (also afficionado), buff, bug, devotee, enthusiast, fanatic, fancier, fiend, fool, freak, habitué (also habitue), head, hound, junkie (also junky), lover, fan, maven (also mavin), nut, suckerRelated Words groupie; admirer, amateur, collector, connoisseur, dilettante; authority, expert; adherent, convert, cultist, disciple, follower, hanger-on, votary; advocate, apostle, backer, champion, evangelist, exponent, friend, patron, promoter, proponent, supporter; partisan (also partizan), zealot; booster, rooter, well-wisher; faddistNear Antonyms nonadmirer; belittler, carper, critic, detractorAntonyms nonfan