I ask because the way the term is thrown around it seems to simply mean anyone that you dislike. If Kelly Slater burned you on a wave you could call him a kook and that would be perfectly acceptable. According to the Urban Dictionary, however, a kook is
"most often used by aggro locals, to describe any surfers that: ... pretend like they can surf when, in reality, they suck-ass. don't follow the rules of the lineup. show up in the lot with a frappachino, excited about 2-footers."
I think the term should apply to:
1) Anyone on a softy.
2) Any longboarder who goes straight and doesn't do any cool turns or hang-ten and stuff (I don't know longboarder lingo).
3) Anyone on a kneeboard... is an enigma, because why?
4) Anyone on a surf SUP without exception.