baddie(or baddy), beast, brute, caitiff, devil, evildoer, fiend, heavy, hound, knave, meanie(also meany), miscreant, monster, nazi, no-good, rapscallion, rascal, reprobate, rogue, savage, scalawag(or scallywag), scamp, scapegrace, scoundrel, villain, wretch

villainessblackguardcriminal, crook, culprit, felon, lawbreaker, malefactor, offender, perp, perpetrator, transgressorsinner, trespasser, wrongdoercad, heel, serpent, snake, viperbandit, bravo, desperado, outlawcon, convict, jailbirdassassin, cutthroat, gangster, goon, gunman, hoodlum, hooligan, racketeer, ruffian, thugrough, rowdy, toughloser, lowlife, ne'er-do-well, stinker, trash