Elite - Stemming from eligere (choosing), an elite is a selected circle of individuals. Commonly, the reason for the choice is an extraordinary exhibition of a certain characteristic (Loyalty, Skill, Knowledge, Power etc etc).

Elitism - Consequently, elitism refers to the belief in the superiority of elites and commonly the idea they should be fostered/supported/praised etc (for example, the idea that rich people should not have to pay taxes because they'd know better than the state how to handle money)

Elitist - A person with the previously mentioned belief.