Source : Webster's Revised Unabridged Dictionary (1913)

Protest \Pro*test"\, v. t.
   1. To make a solemn declaration or affirmation of; to
      proclaim; to display; as, to protest one's loyalty.

            I will protest your cowardice.        --Shak.

   2. To call as a witness in affirming or denying, or to prove
      an affirmation; to appeal to.

            Fiercely [they] opposed My journey strange, with
            clamorous uproar Protesting fate supreme. --Milton.

   {To protest a bill or note} (Law), to make a solemn written
      declaration, in due form, on behalf of the holder, against
      all parties liable for any loss or damage to be sustained
      by the nonacceptance or the nonpayment of the bill or
      note, as the case may be. This should be made by a notary
      public, whose seal it is the usual practice to affix.
      --Kent. Story.