Kylie: the logic in the other post fails at one point.
Characters in MMOs are just electronic progression from characters in paper & dice RPGs.
A definition that is ALSO not in that list of definitions for the word, but well over 30 years old and in use even outside computer gaming by tens of millions of people.
Character, as a player's representation in a game, with the player making all the decisions for the character, goes back to at least 1974 and D&D. Whether the game is one using miniatures, played out in RL surroundings (LARPs) or computer-based, the characters are still characters, by that definition.
BTW, one of the defining elements of "toons" in the cartoon definition, was that the toons were "talkies". This breaks the pretense of linking the word "toon" to MMOs, as the player characters don't talk without the assistance of things like TS & vent (and then, 95% of the chatter is Out of Character) - they present word balloons, in effect, like an animated comic strip. The closest thing to "toons" in computer games are talking NPCs, and those tend to be in non-Online games.