fiend

1 a mean, evil, or unprincipled person even the utter horror of the terrorist attack did not deter some fiends from going on a looting spree Synonyms baddie (or baddy), beast, brute, caitiff, devil, evildoer, villain, heavy, hound, knave, meanie (also meany), miscreant, monster, nazi, no-good, rapscallion, rascal, reprobate, rogue, savage, scalawag (or scallywag), scamp, scapegrace, scoundrel, varlet, wretchRelated Words villainess; blackguard; criminal, crook, culprit, felon, lawbreaker, malefactor, offender, perp, perpetrator, transgressor; sinner, trespasser, wrongdoer; cad, heel, serpent, snake, viper; bandit, bravo, desperado, outlaw; con, convict, jailbird; assassin, cutthroat, gangster, goon, gunman, hoodlum, hooligan, racketeer, ruffian, thug; rough, rowdy, tough; loser, lowlife, ne'er-do-well, stinker, trashNear Antonyms angel, innocent, saint; hero

2 a person who regularly uses drugs especially illegally the miserable, wasted lives of narcotic fiends Synonyms addict, dopehead, druggie (also druggy), doper, freak [slang], head, hophead [slang], hype [slang], junkie (also junky), stoner, userRelated Words acidhead, cokehead, crackhead, pothead, speed freak; burnoutAntonyms nonaddict, nonuser

3 a person with a strong and habitual liking for something comic-book fiends seem to have their own little world Synonyms addict, aficionado (also afficionado), buff, bug, devotee, enthusiast, fanatic, fancier, fan, fool, freak, habitué (also habitue), head, hound, junkie (also junky), lover, maniac, 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

4 an evil spirit the legend that a fiend continues to haunt what was once the castle's torture chamber Synonyms cacodemon, devil, demon, ghost, ghoul, ghoulie, imp, shaitanRelated Words hag [archaic], lamia, vampire; incubus, nightmare, succubus; afreet (or afrit), genie, jinni (or jinn also djinni or djinn); apparition, banshee, bogey (also bogie or bogy), bugbear, familiar, familiar spirit, genius, phantasm (also fantasm), phantom, poltergeist, shade, shadow, specter (or spectre), spirit, spook, vision, wraith; brownie, dwarf, elf, faerie (also faery), fairy, fay, gnome, goblin, gremlin, hobgoblin, kobold, leprechaun, pixie (also pixy), puck, sprite, troll; monster, ogreNear Antonyms angel

5 the supreme personification of evil often represented as the ruler of hell he swore that not even the fiend could tempt him to eat that dessert Synonyms archfiend, Beelzebub, devil, Lucifer, Old Nick, Satan, serpentRelated Words deuce, dickens; Mephistopheles

6 a person with a high level of knowledge or skill in a field our in-house computer fiend fixed the problem in no time Synonyms ace, adept, artist, authority, cognoscente, connoisseur, crackerjack (also crackajack), dab [chiefly British], dab hand [chiefly British], expert, geek, guru, hand, hotshot, maestro, master, maven (also mavin), meister, past master, proficient, scholar, shark, sharp, virtuoso, whiz, wizardRelated Words pro, professional; consultant, hired gun, specialist; addict, aficionado (also afficionado), buff, devotee, enthusiast, fan; craftsman, journeyman; all-rounder [British], jack-of-all-trades, Renaissance man; mistressNear Antonyms apprentice, beginner, neophyte, novice; dabbler, dilettante; layman, nonprofessionalAntonyms amateur, inexpert, nonexpert