A strict follower of a doctrine.
One who believes dogmatically in something regardless of evidence or even conclusive proof that the thing is false or was staged; one who has true-believer syndrome.
Used other than figuratively or idiomatically: see true, believer.
A devout or zealous worshipper.
A person, such as a monk or nun, who lives a religious life according to vows they have made.
A loyal supporter or devoted admirer of a person or institution.
A devotee of a particular religion or cult.
Someone who is devoted to a particular pursuit etc.
Consecrated by a vow or promise; consequent on a vow; devoted; promised.