Elitist is another word for snob. If you wear only the finest silk suits, expect caviar at every meal, and refuse to speak to anyone who doesn't have a PhD, then you might be an elitist.
A fairly recent addition to the English language, the noun elitist, came about from a mix of elite + ist in 1950. Carlyle, Freud, and Nietzsche were all considered to be the original elitists. Elite, from which elitist was formed, evolved much earlier, in 1823, from the French élite, meaning “selection, choice.” Synonyms for elitist include highbrow, pompous person, social climber, and stuffed shirt.