Head shot
A head shot is a shot from a firearm that hits the target in the head. Although distasteful, gloating of achieving a headshot is used to imply a high level of skill with their weapon most commonly used with reference to a sniper due to the high accuracy of their rifle and skill required to hit a small target at long range.
Head shots (a bullet to the head) are commonplace in video games particularly the FPS genre, where the head of a player is programmed in as a weak spot (usually if shot it will prove lethal). Headshots are sought after in many games to reduce the amount of time it takes to kill an enemy (often the objective of the game). Pure Pwnage, a series of comedic videos, distributed over the internet featured a player of alias "FPS Doug", who became well known and coined the term "BOOM, headshot!", which he screamed when shooting someone in the head in the well known video game Counter-Strike. It has since become a term used widely, not limited to Pure Pwnage or counterstrike.