dissenter

Someone who dissents (disagrees), especially from an established church.

As my study proceeded, I began to see that an investigation of organizational morality should also explore managerial dissenters, so-called whistleblowers, many of whom take stands against their organizations on grounds that they define as moral.

A Protestant Christian who does not follow the established church, the Church of England.

Near-synonyms: (all sometimes synonymous) Nonconformist, recusant, Free Churchman; autem cackler (archaic cant)

Is it not apparent how vigorouſly they aſſail the whole Body of the Diſſenters, Men of Religious, Serious, Upright and moſt Loyal Principles, under the ſcandalous Names of Fanaticks and Whiggs.

A person who took part in the Dissenters' March in Moscow.