any English Protestant who does not conform to the doctrines or practices of the established Church of England. The word Nonconformist was first used in the penal acts following the Restoration of the monarchy (1660) and the Act of Uniformity (1662) to describe the conventicles (places of worship) of the congregations that had separated from the Church of England (Separatists). Nonconformists are also called dissenters (a word first used of the five Dissenting Brethren at the Westminster Assembly of Divines in 1643–47). Because of the movement begun in the late 19th century by which Nonconformists of different denominations joined together in the Free Church Federal Council, they are also called Free Churchmen.

The term Nonconformist is generally applied in England and Wales to all Protestants who have dissented from Anglicanism—Baptists, Congregationalists, Presbyterians, Methodists, and Unitarians—and also to independent groups such as the Quakers, Plymouth Brethren, English Moravians, Churches of Christ, and the Salvation Army. In Scotland, where the established church is Presbyterian, members of other churches, including Anglicans, are considered Nonconformists.