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.

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.

• Any of several denominations of Christianity that separated from the Roman Catholic church based on theological or political differences during the Reformation. The term is also used broadly to indicate modern Christian denominations not belonging to the Catholic or Orthodox traditions.
  
• of greater quality or merit.
       
• a protestant effort
       
• protestant work ethic