The Collaborative International Dictionary
Campbellite \Camp"bell*ite\, n. [From Alexander Campbell, of Virginia.] (Eccl.) A member of the denomination called Christians or Disciples of Christ. They themselves repudiate the term Campbellite as a nickname. See Christian, 3.
Douglas Harper's Etymology Dictionary
1830, follower of Alexander Campbell, preacher from Virginia, U.S.A. They called themselves Disciples.
Wikipedia
Campbellite is a mildly pejorative term referring to adherents of certain religious groups that have historic roots in the Restoration Movement, among whose most prominent 19th century leaders were Thomas and Alexander Campbell. Members of these groups generally consider the term "Campbellite" inappropriate, saying that they are followers of Jesus, not Campbell. They draw parallels with Martin Luther's protest of the name " Lutherans" and the " Anabaptists" protest of the name given to them by their enemies. With specific reference to the early Restoration Movement, "[t]he terms Campbellism and Campellites were universally rejected by those to whom they were applied."
Usage examples of "campbellite".
Catholics, the Methodists, the Presbyterians, the Congregationalists, the Baptists, the Spiritualists, the Mormons, the Shakers, the Quakers, the Jews, the Campbellites, the infidels, the Christian Scientists, the Mind-Curists, the Faith-Curists, the train-robbers, the White Caps, the Moonshiners.
The Campbellites had merely an overgrown cottage organ, but they put in a cornet to help out— this in the face of a protest from the conservative element that true religion did not harmonize with any "brass-band trimmings.
If the Zion Church gave a mush-and-milk sociable, it was only natural that the Campbellites, in their endeavor to retain a hold on the friendly sympathies of Musselwhite, should almost immediately make announcement of a rummage party or an old people's concert.
The Campbellites had their Sunday-school in the morning, preceding the regular service, and the Methodists had theirs in the afternoon.
The rivalry between the Methodists and the Campbellites touched perihelion on Christmas Eve.
One year the Campbellites varied the programme by having a scenic chimney-corner erected back of the pulpit.
It's too much like trailin' along behind the Campbellites and takin' their dust.