Merriam-Webster Collegiate Dictionary - protestant

 I. noun  Etymology: Middle French, from Latin ~-, protestans, present participle of protestari  Date: 1539  1. capitalized  a. any of a group of German princes and cities presenting a defense of freedom of conscience against an edict of the Diet of Spires in 1529 intended to suppress the Lutheran movement  b. a member of any of several church denominations denying the universal authority of the Pope and affirming the Reformation principles of justification by faith alone, the priesthood of all believers, and the primacy of the Bible as the only source of revealed truth; broadly a Christian not of a Catholic or Eastern church  2. one who makes or enters a protest  • Protestantism noun  II. adjective  Date: 1539  1. capitalized of or relating to Protestants, their churches, or their religion  2. making or sounding a protest the two ~ ladies up and marched out — Time