1. a person who avoids work and sponges on others; loafer; idler.
2. a tramp, hobo, or derelict.
3. Informal. an enthusiast of a specific sport or recreational activity, esp. one who gives it priority over work, family life, etc.: a ski bum; a tennis bum.
4. Informal. an incompetent person. 5. a drunken orgy
7. Slang. to ruin or spoil: The weather bummed our whole weekend.
9. to live as a hobo.
11. disappointing; unpleasant.
12. erroneous or ill-advised; misleading: That tip on the stock market was a bum steer.
13. lame: a bum leg.