A group of people working together in online multiplayer games. They may just play together for fun, or have training sessions and compete in tournaments.
While there are exceptions, a majority of clans are filled with holier-than-thou
assholes who think they're really something because they have a tag in front of their nickname. Any questioning of clan members invariably results in getting insulted repeatedly, so it's best to just let them be idiots and remember what it was like to be a teenager on the Internet anonymously.
Clanners need to get outside more often.