Usually a response.
Most common definitions.
Won't work, Can't do it, No, Don't think so, Not even, No go. etc etc.
Commonly used in Bay Area slang.
Used as: No, Don't think so
Person: Aye breh you gon come through to the party tonight.
Person: Its bad i think breh.
Used as: No, Not even
Person: Damn nikka you homo for him haha.
Person: *shakes head* its bad breh.