1. [1910s] a metaphorical part of the body.
2. [1950s] the buttocks; in up the bazooka
3. [1950s] the head, the mind, with implications of stupidity.
4. [1950s+] the penis.
5. [2000s] (US black) an especially large and potent marijuana cigarette, laced with cocaine [note basuco n.].
6. [2000s] (drugs) cocaine, crack cocaine.
7. [1990s+] (US drugs) a cigarette that mixes coca paste and tobacco.
[1980s+] (US) a general intensifier, blatantly, excessively, totally, reprehensibly, in large quantities.