plural of Old Believer

(religion) Any of those who separated from the official Russian Orthodox Church after 1666 as a protest against church reforms introduced by Patriarch Nikon between 1652 and 1666. They continue liturgical practices which predate the reforms.

plural of true believer

alternative spelling of nonbeliever

someone who shares one's faith; a brother in faith

(rare) Someone who hides their belief.

plural of crypto-believer

(idiomatic) An emphatic form of believe me: you (the subject) had better believe me (the speaker).

Alternative form of would you believe it

A phenomenon in which witnesses to a staged event continue to believe in its authenticity even after it has been debunked.