This is the University of Chicago definition. Also known as That Guy.
The "That Kid" is, in short, the kid in your class who everybody hates. He consistently attempts to impress the professor with references to books and topics that ultimately irrelevant to the topic and class at hand. He uses big words which he has little grasp of, and quotes authors and thinkers in a nonchalant and usually incorrect manner. He will argue with the professor over anything in a desperate attempt to appear smart. Sometimes, he will go so far as to try and correct the professor--this always fails, because he is an idiot. It is unknown whether "That Kid" really believes in himself, though it is clear that even if he does not, he is still a raging douchebag.
Possibly and probably related to the hipster.
"Dude, who's that asshole who keeps trying to prove the calculus professor wrong?"
"Oh, it's the class That Kid. Fucktard doesn't understand that calculus is a fucking exact science. The professor looks like he's going to beat the shit out of somebody."
*That Kid raises hand*
"sigh...yes, That Kid?"
"Well, sir, I have to disagree with your methodology in addressing this query. You see, I read in my theory class that Marx addresses the dichotomy between the words therefore and vis a vie and conflicts concordingly with your point of view."
"Are you fucking retarded, That Kid? Sit the fuck down."
"How was class?"
"Oh, fucking god, it was terrible. I'm in a class full of That Kids. They had an argument about "the nature of what is" and I felt like shooting myself."