Adjective. Someone who's against a lot of things, and is very political in their arguments against other people. No matter what someone says, they will have an argument against it.
Julia: "Ugh this meat is yuck."
Cristina: "There are millions of starving children in Ethiopia who would kill to have one morsel of your meat, and you're not eating it on the basis that "it's yuck"? You have no consideration for anyone."
Julia: "Ugh you're so college."