term used when dealing with a boy that does nothing for you or the relationship. Most of the time he just sits around and waits for you to do whatever it is he wants. Takes no initiative... sort of like a homeless bumb would. The "ass nigga" is added to add more emphasis to how lazy he is.
Girl: "Omg I'm so sick of Tyrone, we don't go nowhere we just sit in the house while he plays video games"
Girl's friend: "Girl plz, you need to drop him, that's a bumb ass nigga"