A gangster is a member of an organized criminal gang. Gangsters make money through illegal activities like robbery, extortion (forcing people to pay money through threats), smuggling, and controlling illegal businesses. They typically operate as part of a structured group with leaders, rules, and territories they claim as their own.

The most famous American gangsters operated during Prohibition in the 1920s and 1930s, when alcohol was illegal. Criminals like Al Capone built powerful organizations that smuggled and sold alcohol, making enormous profits while avoiding the law. These gangster organizations, sometimes called the mob or mafia, used violence and intimidation to protect their operations and eliminate rivals.

Gangsters differ from ordinary criminals because they work within organized groups that function almost like illegal businesses. A shoplifter or pickpocket might work alone, while gangsters coordinate with others, follow their organization's rules, and share profits with their gang.

Movies and television often glamorize gangsters, making their lives seem exciting or romantic. In reality, gangsters cause real harm to communities through violence, fear, and corruption. Many gangsters end up in prison or die in conflicts with rival gangs. Calling someone a gangster means they're a serious criminal involved in organized crime who has broken many laws and harmed many people.