An extreme fan of the official Star Wars Canon content such as the infamous sequel trilogy of movies or the TV show Star Wars: The Clone Wars (2008-2020), for examples.
Sometimes Canon Clowns are bold or stupid enough to say that the Star Wars EU sucks, which it does not.
Some canon fan: "Hurr Durr Legends sucks Canon rocks"
Anyone with a brain: "You canon clowns can't be taken seriously."