Synonyms for Heresy:

n.

absolution, angel, angelic, archangel, article of faith, blaspheme, blasphemous, bless, blessing. decadence, depravity, enormity, evil, excess, immorality, iniquity, villainy, wrong. cognition (noun)
heterodoxy, unorthodoxy.
difference of opinion (noun)
dissidence.
heresy (noun)
heterodoxy, unorthodoxy.
impiety (noun)
blasphemy.
nonconformity (noun)
agnosticism, apostasy, blasphemy, dissent, protestantism, revisionism, schism, secularism, sin, doctrinal divergence.
sectarianism (noun)
atheism, barbarism, bohemian, demonism, demonolatry, dissidence, fetishism, heathenism, heterodoxy, iconolatry, idolatry, nonconformity, paganism, pantheistic, sectarianism, Denominationalist, non-belief, non-religiousness, factionalism, non-orthodoxy.
unorthodox opinion, especially in religious matters (noun)
agnosticism, apostasy, atheism, blasphemy, dissent, dissidence, heterodoxy, nonconformity, paganism, revisionism, schism, sectarianism, secularism, sin.

Other synonyms:

nonconformity
dissent.
Other relevant words:
agnosticism, apostasy, blasphemy, dissent, revisionism, schism, secularism, sin, unorthodoxy, wrong.

Usage examples for heresy

  1. The penalty will not be lightened only because you did not invent the heresy – The Thing in the Attic by James Benjamin Blish
  2. Music and the Catholic religion, in the midst of a city which had fallen into the Protestant heresy had been the bond between them. – The Complete Historical Romances of Georg Ebers by Georg Ebers
  3. This was heresy from the Davidian point of view, and David eventually convinced him of it. – A Text-Book of the History of Painting by John C. Van Dyke