I often hear the phrase, "That is imba" in the video gaming community. It seems to refer to something powerful or unskillful:
Hunters are so imba.
Grenade launchers are imba!
But I have also noticed that it is often used tongue-in-cheek or sarcastically to mock people complaining about something being altered in the game:
"Waa... they nerfed my class! Now that other class is imba!" QQ more, please.
What does "imba" mean and where did the term come from? Is it used outside of gaming? My first encounters with it related to Starcraft which has a well known Korean professional gaming league. Is "imba" a loan?