If you ask what's an elitist, you're going to get two obvious replies; 'an elitist is a prick' and the dictionary definition of an elitist. Dictionaries are alright for practicing your spelling and loads of other stuff, but they're terrible for settling arguments. Also, to say an elitist is just a good player that's a prick is obviously an incomplete definition.
So how should we define an elitist? Some might say a mix between the two, I disagree; I think the more important focus isn't how someone acts or feels but rather how someone fundamentally views the game (taken to the extreme that is elitism). Perfectly polite people could be elitist for example, but they'd also have to have an elitist viewpoint of the game. This allows us to use elitist as a proper description of a player rather than just an insult.
So what's the elitist view of the game? You guys have your own answers to this, I'm not entirely sure where to stand of course. I will say it's more than just playing the game competitively though.