An "unc" is typically an Italian-American gangster/mobster, often living around the area of New York. (However there have been numerous sightings around various football stadiums in England)
Aesthetically, they are often very smartly dressed, with neat, well-kept hair; however often hair can be gelled back/ combed over.
Typically using a specific Italian-American accent, words such as "burger" are pronounced "boy-ger". Often deal in organised crime and football management.
...And UNC! said "Capiche, I'm gonna take you to Copacabana beach if you don't give me da money"