any Western Christian who is not an adherent of a Catholic, Anglican, or Eastern Church.

an adherent of any of those Christian bodies that separated from the Church of Rome during the Reformation, or of any group descended from them.

(originally) any of the German princes who protested against the decision of the Diet of Speyer in 1529, which had denounced the Reformation.

( lowercase ) a person who protests.

belonging or pertaining to Protestants or their religion.

( lowercase ) protesting.

noun

amish , anglican , calvinist , episcopalian , lutheran , mormon , shaker , unitarian