Source : Webster's Revised Unabridged Dictionary (1913)

Protestant \Prot"es*tant\, a. [Cf. F. protestant.]
   1. Making a protest; protesting.

   2. Of or pertaining to the faith and practice of those
      Christians who reject the authority of the Roman Catholic
      Church; as, Protestant writers.

Protestant \Prot"es*tant\, n. [F. protestant, fr. L. protestans,
   -antis, p. pr. of protestare. See {Protest}, v.]
   One who protests; -- originally applied to those who adhered
   to Luther, and protested against, or made a solemn
   declaration of dissent from, a decree of the Emperor Charles
   V. and the Diet of Spires, in 1529, against the Reformers,
   and appealed to a general council; -- now used in a popular
   sense to designate any Christian who does not belong to the
   Roman Catholic or the Greek Church.

Source : WordNet®

Protestant
     n 1: an adherent of Protestantism
     2: the Protestant churches and denominations collectively [syn:
         {Protestant Church}]

Protestant
     adj 1: of or relating to Protestants or Protestantism; "Protestant
            churches"; "a Protestant denomination"
     2: making a protest [syn: {protesting(a)}]