Organized crime is a category of transnational, national, or local groupings of highly centralized enterprises run by criminals to engage in illegal activity, most commonly for profit. Some criminal organizations, such as terrorist groups, are politically motivated. Sometimes criminal organizations force people to do business with them, such as when a gang extorts money from shopkeepers for "protection". Gangs may often be deemed organized crime groups or, under stricter definitions of organized crime, may become disciplined enough to be considered organized. A criminal organization can also be referred to as a gang, mafia, mob, ring, or syndicate; the network, subculture, and community of criminals may be referred to as the underworld. Sociologists sometimes define a "mafia" as a type of