English Synonyms and Antonyms, by James Champlin Fernald
An adherent is one who is devoted or attached to a person, party, principle, cause, creed, or the like. One may be an aider and supporter of a party or church, while not an adherent to all its doctrines or claims. An ally is more independent still, as he may differ on every point except the specific ground of union. The Allies who overthrew Napoleon were united only against him. Allies are regarded as equals; adherents and disciples are followers. The adherent depends more on his individual judgment, the disciple is more subject to command and instruction; thus we say the disciples rather than the adherents of Christ. Partisan has the narrow and odious sense of adhesion to a party, right or wrong. One may be an adherent or supporter of a party and not a partisan. Backer is a sporting and theatrical word, personal in its application, and not in the best usage. Compare ACCESSORY.