How about a nice little fuck off
or being more polite and tell him to get out of your personal space this very moment, with a side comment of leave me alone?
Mom had a stalker once, and she couldn't get rid of him because of mixture of being too nice to him, and showing confusing signs due to being too aware of wanting to be polite and a nice dose of social awkwardness.
I caught him ringing her doorbell, told him where to stick, went upstairs and started laughing because he was sooo pathetic, which I told Mom once I reached her flat (and the window was open and he did hear me) that was the end of that.
Be a bitch and it'll work out