A person (particularly a non-Korean or mainly a non-Asian girl) who is obsessed with Korean men and is desperate to either be friends with them, be in a relationship with them, and or marry a them. They are also commonly known to overuse the word "oppa" (Korean word for a male that is older than you; term used by females) when talking not only about Korean males, but to other Asian men who happen to look Korean.
Guy 1: Dude this girl in my Korean class is a total oppa hunter.
Guy 2: Really? How so?
Guy 1: When I told her that I'm Korean she wouldn't stop calling me 'oppa' and then she wouldn't stop talking about her favorite K-POP groups and singers.
Guy 2: She sounds annoying.
Guy 1: You have no idea. She even called the Taiwanese guy in our class 'oppa'.
Guy 2: Is she even Asian?
Guy 1: Nah, she's white.