Gangster

A gangster, mobster, or gangsta is a criminal who is a member of a crime organization, such as a gang. The terms are widely used in reference to members of gangs associated with American prohibition and the American offshoot of the Mafia, such as the Chicago Outfit or the Five Families. The related word "mobster" is a term derived from Latin and Aramaic. A gang is a group of people who, through the organization, formation, and establishment of an assemblage, share a common identity.
In early usage, the word gang referred to a group of workmen. In the United Kingdom the word is still often used in this sense.