Headshot — a hit to a character's head area. In CS2, as in other shooters, the damage from a shot depends on where the bullet lands: the body, limbs, or head. A hit to the head almost always deals maximum damage, and with most weapons a single such shot kills the opponent instantly, regardless of how much health they had left.
The word comes from the English "head" and "shot" and has become fixed in gaming slang without translation — even players who barely know English use it directly.
Why it's not just luck
In CS2, a hit to the head is a direct result of crosshair control and understanding weapon recoil mechanics. Players train what's called crosshair placement — the habit of keeping the crosshair at head level before the opponent even appears in view. This dramatically increases the chance of a headshot in the first split seconds of contact, when the decision is made faster than conscious reaction can kick in.
Headshot statistics are one of the metrics used to evaluate a shooter's skill level. A high headshot percentage (usually measured as the share of headshots out of all kills) indicates good aim and stable aiming, rather than lucky random shots.
Where the term is used
The word is used practically everywhere shooting in CS2 is discussed: in broadcasts, commentators call impressive kill streaks "headshots in a row," match statistics separately display each player's headshot percentage, and training modes have dedicated maps and modes specifically designed to practice hitting the head.
It's important to distinguish a headshot as a one-time hit from a player's overall accuracy: you can land one impressive headshot by chance, but a consistently high percentage of such hits over a long series of matches is already an indicator of skill, not luck.