But "to troll" as used by mrodoc is surely a verb. So if a troll is someone who dangles bait (in the form of a provocative post) behind his boat, so to speak, isn't this a case of a verb being nouned rather than a noun being verbed?
"To troll" meaning to sit under a bridge and wait for a suitable-sized billy goat to cross over would be a better example of a noun being verbed.
Still think the best example of a troll that I've seen was the one in Moria in the Lord of the Rings. (Though - to keep on topic - I can't remember whether it was naked or not.)