A vicar is a member of the clergy who is not high-ranking but is still considered a holy representative of the church.
Vicars are set slightly below the official head of a congregation or parish, sometimes acting as an agent or substitute clergyman. Originally considered an earthly go-between for man and God, the meaning of the word moved diminished as the vicar became sort of a "deputy" priest or parson. You can find a vicar in the Church of England, and also in the Episcopal and Roman Catholic churches. Consider that "vicarious" means something taking another's place — that's what a vicar does.