2.Noun: A person who is the best of the best at what they do professionally and/or personally. Being a Gangster goes hand-in-hand with being self confident, secure and uninhibited.
Person 2: Yeah, she is totally gangster.
2. Mark, our loan officer, helped us get our house refinanced after three other lenders said it was impossible. He is a total Mortgage Gangster!
2b. Student 1: Mr. Hall is the best science teacher ever. Student 2: I know. I never would have passed the test without him. Student 1: He is such a science gangster. Student 2: Word!