When someone has a sense of, or knows how to handle themselves in a rough neighbourhood or ghetto. People can be street smart regardless of their style. It usualy depends on where or how they were raised. It also can mean how well someone can handle themselves in an unfamiliar neighbourhood or city streets.
Christos the greek wasn't a thug but he was raised in a ghetto neighbourhood and was street wise. He had no problem walking through a rough neighbourhood at night.
On the other hand Steve the wigger considered himself a thug but was raised in a fairly rich, high class neighbourhood. He wasn't street wise and when he needed to walk through the projects he was so afraid he almost shit his pants and took a cab home instead.
Prices shown in USD.