[her.e.sy] n, pl -sies [ME heresie, fr. OF, fr. LL haeresis, fr. LGk hairesis, fr. Gk, action of taking, choice, sect, fr. hairein to take] (13c) 1 a: adherence to a religious opinion contrary to church dogma b: denial of a revealed truth by a baptized member of the Roman Catholic Church c: an opinion or doctrine contrary to church dogma
2. a: dissent or deviation from a dominant theory, opinion, or practice b: an opinion, doctrine, or practice contrary to the truth or to generally accepted beliefs or standards