heresy Definition

heresy
noun heresies

1. An opinion or belief contrary to the authorized teaching of the religious community to which one ostensibly belongs.

Thesaurus: dissent, apostasy, dissidence, heterodoxy, iconoclasm, nonconformity, revisionism; Antonym: orthodoxy.
2. An opinion opposed to the conventional or traditional belief; heterodoxy.

Etymology: 13c: from Greek hairesis choice.