Aimbot is a term used to describe software that automatically aims at an opponent in a multiplayer video game. It is essentially cheating and is therefore banned on most multiplayer servers in the games that it is available for, many of which actively seek out behaviour consistent with aim botting to kick and ban the player involved.
Aim bots use a variety of methods to achieve their results, but the basic principle is that they are able to detect an enemy in-game, and using various processes will then automatically aim at that enemy in order to maximise the likelihood of a hit. Usually this will involve detecting the position of the enemy and then altering the players own aim in-game in order to fire at the correct point on their opponent.
Keep Them Short and Simple
Injection aimbots use data from the screen or even the actual game itself to determine whether an enemy is present, and where they are located, enabling extreme accuracy in an instant. This means that players can fire at an enemy almost immediately after they have been spotted, and this can be difficult for spectator players to pick up on, as it will likely take a little time for their eyes to recognize the enemy.
More advanced aimbots will also utilize information about the current state of the game, including function adresses that can be read by debuggers to get access to data structures that include the world positions of other players. This allows the aimbot to be able to scan for an enemies current position and then use this to calculate how much to move in the direction of the player in order to line up with them, which can make it very difficult for non-hackers to tell that someone is using an aimbot.