Protestant meaning : A member of any of several Christian denominations which separated from the Roman Catholic Church based on theological or political differences during the Reformation (or sometimes later). (history) A member of the Church of England or Church of Ireland, as distinct from Protestant nonconformists or dissenters Of or pertaining to several denominations of Christianity that separated from the Roman Catholic Church based on theological or political differences during the Reformation. One who protests; a protester. Protesting