believer
n. countablen. someone who is sure that something is true or good. You can use this for religious faith or just for having strong confidence in an idea.
n. a person who maintains a firm conviction in the truth or efficacy of something. Often followed by the preposition 'in' to specify the object of faith or confidence.
She is a firm believer in the power of daily exercise.
As a true believer in lifelong learning, he enrolled in a new university course at the age of eighty.
While some critics remained skeptical of the new economic policy, the prime minister found a staunch believer in the head of the central bank.
From Middle English bilevar, bileever, belever, equivalent to believe + -er.
Commonly pairs with the preposition 'in' to indicate the subject of the belief.
a believer of justicea believer in justiceThe noun believer almost always takes the preposition 'in' rather than 'of' when describing the object of belief.