Fanderization (or Fan-derization) is an act of fans flanderizing (exaggerating and suppressing certain traits) a character. Usually through memes and other fan-generated content.
Unlike actual flanderization, the official and canon form of the character remains unchanged, but the way fans perceive and understand the character is altered externally.
Also see "fanon vs. canon."
X character has been memed to death. They don't even act like that in the show. The fans just fanderized them into a spineless jokester.