Noun | 1. | ![]() social group - people sharing some social relation yakuza - organized crime in Japan; an alliance of criminal organizations and illegal enterprises gang, mob, pack, ring - an association of criminals; "police tried to break up the gang"; "a pack of thieves" underworld - the criminal class Sicilian Mafia, Maffia, Mafia - a secret terrorist group in Sicily; originally opposed tyranny but evolved into a criminal organization in the middle of the 19th century Black Hand - a secret terrorist society in the United States early in the 20th century Camorra - a secret society in Naples notorious for violence and blackmail crime syndicate, syndicate, mob, family - a loose affiliation of gangsters in charge of organized criminal activities |