Word Study
gangster
OXFORD DICTIONARY
gangster, n. a member of a gang of violent criminals.
Derivative
gangsterism n.
THESAURUS
gangster
Judas, Mafioso, bad person, bandit, betrayer, brigand, convict, criminal, crook, dacoit, deceiver, delinquent, desperado, desperate criminal, double-dealer, evildoer, felon, fugitive, gallows bird, gaolbird, goon, gunman, gunsel, gunslinger, hit man, hood, hoodlum, hooligan, jailbird, lawbreaker, malefactor, malevolent, malfeasant, malfeasor, misfeasor, mobsman, mobster, mugger, outlaw, public enemy, quisling, racketeer, robber, ruffian, scofflaw, sinner, skinhead, soldier, swindler, thief, thug, torpedo, tough, traitor, transgressor, two-timer, villain, worker of ill, wrongdoerFor further exploring for "gangster" in Webster Dictionary Online