Smartass

There's a difference between sarcasm and smartass.   Plus to be a smartass, but that's kinda a contradictory in terms; if you're not smart you're just an ass.  That being said if you're going to run off at the mouth at least know what you're talking about, just don't run off at the mouth and not because you just make yourself look more stupid then you already are.  Rant officially over