One who has mastered debating skills.
The local politician proclaimed himself as a masterdebator for constantly winning debates against political opponents.
Usually something said after you and someone else were in an argument, and you totally just left him silent with your comeback. Also usually said with making the motion of stroking your dong for more a greater effect.
Some Punk: Why do you where those clothes?
You: Why are you such a faggot.
Some Punk: Your a faggot, that shirt is hella ugly.
You: Atleast its not as bad as your face.
Some Punk: ...
You: OOO! Thats right bitch, you can't handle this, I'm the masterdebator.