Heretic

Part of speech: noun (n.)

1. One who holds to a heresy; one who believes some doctrine contrary to the established faith or prevailing religion. A man that is an heretic, after the first and second admonition, reject. Titus iii. 10.

2. One who having made a profession of Christian belief, deliberately and pertinaciously refuses to believe one or more of the articles of faith "determined by the authority of the universal church." Addis & Arnold.

Synonyms: Heretic, Schismatic, Sectarian. A heretic is one whose errors are doctrinal, and usually of a malignant character, tending to subvert the true faith. A schismatic is one who creates a schism, or division in the church, on points of faith, discipline, practice, etc., usually for the sake of personal aggrandizement. A sectarian is one who originates or is an ardent adherent and advocate of a sect, or distinct organization, which separates from the main body of believers.