1: The ability to fight while drunk.
2: When you ithink/i have the above skill. Normally involves the wild flailing of limbs and you getting your ass kicked. Much more common than #1.
Hey, what happened to Marty last night?
He started a fight and got drunken-fu'd.
Hey, what happened to jason last night?
He started a fight, thinking he knew drunken fu. Alas, he did not, and he's in county right now.