Seceder

noun

1. One who secedes or withdraws from communion or association with an organization.
2. [capitalized] A member of the Secession Church in Scotland. See Secession Church, under secession.
3. One who secedes.
4. One of a numerous body of Presbyterians in Scotland who seceded from the communion of the Established Church, about the year 1733, and formed the Secession Church, so called.
5. One who secedes, such as from a country or organization