Raped, owned, pwnd etc.
Pretty obvious
Rusher
A person who rushes, or gets to the other team quickly, usually with an SMG, to get a lot of kills.
QUUAAAADDD
Killing four people simultaneously/in quick succession.
Collateral
Two kills with one sniper shot.
360
Crap console / Spinning in a full circle before shooting someone.
Noscope
Sniping someone without scoping in.
And there's moar but I cba