Headshot originated from the game Unreal Tournament, and has been used by FPS players since then. The word is while one is playing an fps, when suddenly out of no where "BOOM, HEADSHOT." When you get a headshot, this may lead to extreme happiness in yourself, because you just pwned that little J00. However, when you are given a headshot, you may tend to scream out, "WTF, Thats Bullshit, LEAVE THE GAME HACKER!"
While playing Counter Strike you may flashbang someone, turn the corner to see them completely blind. You start to shoot at them at point blank, hitting them 2 times, giving them a total of 67 damage. As they become unblind, they will turn and shoot you in the forehead causing instant death. This is known as a "Headshot." Some players will scream out " WHAT THE HELL IS THE TIC RATE IN THIS JOINT?" Others might take it out on things or people around them at the time of the owning.