These words pertain to people who espouse independent or anti-authoritarian views in opposition to the doctrines of a religion or ideology. Heretic refers to a believer who wilfully espouses a tenet that his church has officially declared to be anathema. Taking a stand on an issue the church has not ruled on would not make a person a heretic . And while the church may punish a heretic by ejecting him or, at one time, putting him to death, a heretic’s aim need not be to separate from the church but possibly to stay within and reform it. A schismatic , by contrast, may or may not have serious doctrinal objections to church teachings, but his avowed aim is to establish a separatist faction or competing religious body. A schismatic , furthermore, would most likely be one of a group or its leader, whereas a heretic an be a single individual with or without followers: The early Protestants expected to be condemned as heretics , but didn’t foresee that this would inevitably result in their becoming schismatic .

Dissenter and nonconformist both originally pertained to people who in some way opposed the established Church of England. A dissenter was someone who rejected a particular doctrine without leaving the church, while a nonconformist was anyone who would not give to the established church the loyalty required by law. Roughly speaking, a dissenter criticized from within the Church of England, the nonconformist resisted from without. Sectarian once referred to a schismatic who founded or advocated the founding of a denomination independent of the original church. Later, it could simply indicate a member of any denomination or sect. More recently, the word is avoided altogether because it can imply a superior-inferior relationship between the original church and the later formation.

Dissenter and nonconformist are widely used outside the context of religion. In this case, dissent usually implies someone who is extremely critical of some established order and wishes to reform it: youthful dissenters who were organizing a protest march. Nonconformist , by contrast, more often refers to someone who is idiosyncratic in his personal behaviour and appearance in such a way as to exhibit a sharp departure from custom; the word, thus, need not suggest the advocacy of any formulated ideological stand whatsoever; long-haired nonconformists who were little more than pleasure-seeking exhibitionists and who had no political commitment of any kind. Heretic and schismatic can occasionally be used of people carrying on doctrinal disputes about an authoritarian ideology; in this case, the words often have a humorous or ironic note: those Communists that Stalin decided to condemn as heretics ; the infighting common among Trotskyite schismatics .