1. Someone who deliberately gives others a hard time, is very demanding, or is insulting. Can be considered vulgar. John's boss, Mark, is quite the ball-buster. After completing the project ahead of time and under budget, Mark ordered John to work through the weekend to finish up other meaningless tasks.

2. A particularly challenging or strenuous task. Geez, that problem was a real ball-buster—I can't believe we finally came up with a solution.

3. A woman that men deem intimidating or threatening. Oh, the guys just think Nora's a ball-buster because she's not afraid of them.