Do you have a read on villain that says he's a thinking player or a donkey? Could he possibly be smart enough to be playing off your own aggression?

If the answers here are no, then this looks more like a pair+FD (or less) to me. If that's the case, a push on the turn seems right as checking behind will only invite villain to bluff on the river. If he's scared of a higher (or made) flush at all, a turn bet is the only way to take this down. Betting 6k, as another poster suggested, will leave you with 4k behind. If villain calls this bet and you miss your draw it's likely he has you beat and you'll be in the red zone. Since you're not betgo (sorry betgo, couldn't resist [img]/images/graemlins/tongue.gif[/img]) I would push the turn and hope that villain isn't holding 2 spades so you can push him off the pot. If he calls you still have some outs to the nut flush draw on the river plus the possibility that your A and K outs are still good.