1. An opinion held in opposition to the established or commonly received doctrine, and tending to promote a division or party, as in politics, literature, philosophy, etc.; usually, but not necessarily, said in reproach. New opinions divers and dangerous, which are heresies, And, not reformed, may prove pernicious. (Shak) After the study of philosophy began in Greece, and the philosophers, disagreeing amongst themselves, had started many questions . . . Because every man took what opinion he pleased, each several opinion was called a heresy; which signified no more than a private opinion, without reference to truth or falsehood. (Hobbes)
2. Religious opinion opposed to the authorised doctrinal standards of any particular church, especially when tending to promote schism or separation; lack of orthodox or sound belief; rejection of, or erroneous belief in regard to, some fundamental religious doctrine or truth; heterodoxy. Doubts 'mongst divines, and difference of texts, From whence arise diversity of sects, And hateful heresies by god abhor'd. (Spenser) Deluded people! that do not consider that the greatest heresy in the world is a wicked life. (Tillotson)
3. An offense against christianity, consisting in a denial of some essential doctrine, which denial is publicly avowed, and obstinately maintained. A second offense is that of heresy, which consists not in a total denial of christianity, but of some its essential doctrines, publicly and obstinately avowed. (Blackstone)
When i call dueling, and similar aberrations of honor, a moral heresy, i refer to the force of the greek, as signifying a principle or opinion taken up by the will for the wills sake, as a proof or pledge to itself of its own power of self-determination, independent of all other motives.