It's a bit difficult without context but generally it means "Stop me doing my job", whether that means forcing the person to shut up shop (the most literal usage) or just making it difficult for them to be effective - e.g., heckling a comedian, strongly marking a sports person, etc. I think I've heard it more generally used to imply interference of some sort - preventing someone from contributing to a conversation for example.
I hope that gives you a clue, but of not, maybe you could give a bit more background...?