See Protestant. The legal sense either has the same source or is simply protest + -ant.

protestant

1. Alternative case form of Protestant

   a protestant effort

   protestant work ethic

2. Protesting.
   • 1919, Henry B[lake] Fuller, “Cope Again in the Country”, in Bertram Cope's Year: A Novel, Chicago, Ill.: Ralph Fletcher Seymour, The Alderbrink Press, →OCLC ↗, page 274 ↗:

     He cut his Psychology once or twice, nor could he succeed, during office hours, in keeping his mind on office-routine. His superiors became impatient and then protestant.

   • 1932, Graham Greene, Stamboul Train‎, Penguin, published 1963, Part 4, Chapter 4, p. 191:

     Her sense of desolation, the knowledge that for some reason, God alone knew why, she loved him, made her for a moment protestant. Why not ? Why shouldn’t I write to him?

protestant (plural protestants)

1. (chiefly, legal) One who protests; a protester.
   • 1847 January – 1848 July, William Makepeace Thackeray, Vanity Fair […], London: Bradbury and Evans […], published 1848, →OCLC ↗:

     These are too mean parts of the pageant: and you don't hear widows' cries or mothers' sobs in the midst of the shouts and jubilation in the great Chorus of Victory. And yet when was the time that such have not cried out: heart-broken, humble protestants, unheard in the uproar of the triumph!

   • 1915 November 3, decision in the case of the State of New Mexico v. Garrett, published in 1916 among the Decisions of the Department of the Interior in Cases Relating to Public Lands, volume 44 (edited by George J Hesselman), page 490: In the case of Hyacinthe Villeneuve a homestead entry had been allowed upon a tract of land that had been patented to the Santa Fe Railroad Company, whose grantees had expressed a willingness to reconvey in order that effect might be given to the equities of the homesteader, whereas in the present case the State stands in the position of a protestant.
2. Alternative case form of Protestant

Borrowed from either German Protestant or French protestant, one likely reinforced by the other; equivalent to protest + -ant.

• (RP) IPA: /ˈpɹɒtɪstənt/
• (America) IPA: /ˈpɹɑtɪstənt/

protestant (plural protestants)

1. (Christianity) 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 in some cases later).

   Synonyms: Christian

2. (historical) A member of the Church of England or Church of Ireland, as distinct from Protestant nonconformists or dissenters
   • 1827 [1796] Theobald Wolfe Tone, Memoirs Vol.1 p.64 ↗ (Henry Colburn, London) ed. William Theobald Wolfe Tone:

     To unite the whole people of Ireland; to abolish the memory of all past dissensions; and to substitute the common name of Irishman in place of the denominations of Protestant, Catholic, and Dissenter—these were my means.

   • 1893 June 14, [https://web.archive.org/web/20170310170306/http://hansard.millbanksystems.com/commons/1893/jun/14/commityee-progress-13th-june#S4V0013P0_18930614_HOC_57 Hansard 4th series Vol 13 HC Deb c.1001]

     MR. SEXTON said, he had always understood that the difference between Protestants and Presbyterians was not a difference of creed, but as to episcopacy and practice.

• French: protestant, protestante
• German: Protestant, Protestantin
• Italian: protestante
• Portuguese: protestante
• Russian: протеста́нт
• Spanish: protestante, salvacuatro (Paraguay)

protestant

1. (Christianity) Of or pertaining to several denominations of Christianity that separated from the Roman Catholic Church based on theological or political differences during the Reformation.

   Synonyms: Christian

• French: protestant
• German: protestantisch, evangelisch
• Italian: protestante
• Portuguese: protestante
• Russian: протеста́нтский
• Spanish: protestante