heresiarch UK /hɛˈɹiːzɪɑːk/US /həˈɹiziɑɹk/ noun1 •The founder of a heresy, or a major ecclesiastical proponent of such a heresy.He died in 1223, and seems to have had no successor; not is it an ascertained point that more than one such haeresiarch was ever recognized. — 1838 formsheresiarchs
