Definitions

1. noun

a person who is part of a group of people who commit crimes or engage in violent behavior, especially as a member of a street gang.

“The police were cracking down on local gangsters who had been terrorizing the neighborhood.”

2. verb

to act or behave like a gangster, especially by committing crimes or engaging in violent behavior.

“The young men had started to gangsterize, resorting to violence to get what they wanted.”