One who thinks he/she has done something brilliant by hacking another, when really all he/she has done has ruined a perfectly useful space of time annoying another user with his/her pathetic, destructive behavior.
One who uses cheats or hacks in online multiplayer games such as Counter-Strike. The cheater often has an aimbot, can see players through walls, uses neon colored player models, and has decreased recoil to name a few advantages.