A straight or curious male, that is sexually excited by a Drag Queen, Crossdresser or Tranny. They will hunt them out discreetly whether it be online or at a club. normally to receive or give sexual pleasure for the targeted queen, crossie or tranny
Oh Genel, look at that guy, fussing all over you, he is such a Loon.
In Aberdeen, Scotland, it's local dialect (doric) meaning a young guy. That's probably why there's another definition further up, for fans of the Scottish actor Billy Boyd. Whose not from Aberdeen I think but never mind.