Someone who is obsessively preoccupied with maintaining or improving their physique and thus spends a large amount of time at the gym to do so. After recovering from his surgery, John spent a lot of time at the gym getting his body back into shape. Now he's turned into a total gym bunny.

A sneaker, particularly one worn in gym class or to play sports. Unfortunately, I didn't realize I forgot my gym shoes until I got to the locker room.