a bum, loser, lookin a damn fool
(1) Damn son, why you lookin' like a bassa?
(2) He a damn bassa.
A homeless person. They usually have a mental illness or are addicted to crack or heroin.
If you are underaged and need beer, cigarettes, or a philly blunt, ask a "bassa" to buy it for u. Make sure you give them a quarter afterwards so they can keep up their habit.