Paladin \PAL-uh-din\ noun
1. A knight-errant; a distinguished champion of a medieval king or prince; as, the paladins of Charlemagne.
2. A champion of a cause.
Origin: Paladin derives from Late Latin palatinus, "and officer or the palace," from Latin palatium, "royal residence, palace," from Palatium, one of the seven hills of Rome on which Augustus had his residence.