heresy

vääräoppisuus

kerettiläisyys, vääräuskoisuus puhekieltä A doctrine held by a member of a religion at variance with established religious beliefs, especially dissension from Roman Catholic dogma.
1968, History of Western Civilization, edited by Heyes, Baldwin & Cole, p.47. Macmillan. Library of Congress 67–13596

Heresy meant deliberate departure from the accepted doctrines of the church. It was intellectual and spiritual dissent and concerned the beliefs of Christianity, not the morals of its adherents.