A person who plays video games excessively each and every day, frequently allowing all their free time to be consumed by video games. These individuals frequently think they are smart, but are not as they spend all their time rotting their minds with video games rather than learning new skills. They are frequently quick to anger when losing on a video game because they have lost the ability to fully differentiate between games and reality. Most gamers are socially deficient and have "geek" or "nerd" qualities. Gamers are frequently virgins and rarely have any contact with the opposite sex. In the extremely rare case that a gamer somehow acquires a girlfriend, she usually leaves him within a few weeks after she learns that he is doomed to be a loser for the rest of his life because of his attachment to video games.
If you play video games excessively every day, you're a gamer. If you don't maybe you're not a gamer. If you don't agree with this definition, you can go fuck yourself.