A person who paints his face, for whatever reason.
An example of a facepainter: David Puddy, Elaine Benes' (the "Seinfeld" saga character) coming-and-going boyfriend. He does it "to support his team" - the Devils - in a hockey game. For Elaine's love, he eventually gave it up in favour of chestpainting: obviously, the chest and the face are completely different things.