The act of being killed exceeding quickly. Standardly 1 shot. But in games lacking an 'instagib rifle' (or even anything resembling a gun) is usually taken to mean death in <1-2 seconds.
Unreal: The server had instagib enabled last night. Twas so chaotic my head was reeling after a few rounds.
Battlefield: That guy killed me as soon as I turned the corner.
Defense Of The Ancients: Care man, they will instagib you if you go too far alone.
Originally a bastardization of =/ and =S
Now generally taken for a 'bah/confused/unsure' emotion. Some times directed at the other party(s) and not the speaker.
Zack: Whats wrong with C++?
Owen: Nothing really... just bad memories from school keep me from liking it.
Vance: This thing is driving me nuts...
Vance: Any ideas?