a greb is a person who wants to be an individual, they dress how they like, usually wearing baggy clothes, with skulls or daggers. They have their own fashion, and don't care what others think. They don't all ways try to be differant as some people say, but they simply don't care what other people think of them. Basically they do what the hell they like.
non-greb "hey you, why are you wearing that? The top so doesn't go with the trousers"