A priest was an individual who held authority over religious rites and rituals. In many of Earth's civilisations they held much power and could often determine if an individual lived or died if they broke the religious or cultural laws. (TV: Invasion of the Dinosaurs) Faith was a major component in an individual being a priest, with some demonstrating extraordinary feats through faith. (PROSE: The Sword of Forever)
The religion of Florana in its early days involved priests. One of these was Thane. (AUDIO: The Elite)
The confessional priests of the Church of the Silence were sometimes referred to as Silents. (TV: The Time of the Doctor)
Inca priests used the Great Power to grant superhuman powers. (PROSE: Doctor Who and the Daleks)