Protester

noun
1.
an expression or declaration of objection, disapproval, or dissent, often in opposition to something a person is powerless to prevent or avoid:
a protest against increased taxation.
2.
Commerce.

a formal notarial certificate attesting the fact that a check, note, or bill of exchange has been presented for acceptance or payment and that it has been refused.
the action taken to fix the liability for a dishonored bill of exchange or note.

3.
Law.

(upon one’s payment of a tax or other state or city exaction) a formal statement disputing the legality of the demand.
a written and attested declaration made by the master of a ship stating the circumstances under which some damage has happened to the ship or cargo, or other circumstances involving the liability of the officers, crew, etc.

4.
Sports. a formal objection or complaint made to an official.
verb (used without object)
5.
to give manifest expression to objection or disapproval; remonstrate.
6.
to make solemn or earnest declaration.
verb (used with object)
7.
to make a protest or remonstrance against; object to.
8.
to say in protest or remonstrance.
9.
to declare solemnly or earnestly; affirm; assert.
10.
to make a formal declaration of the nonacceptance or nonpayment of (a bill of exchange or note).
11.
Obsolete. to call to witness.
noun (ˈprəʊtɛst)
1.

public, often organized, dissent or manifestation of such dissent
(as modifier): a protest march

2.
a declaration or objection that is formal or solemn
3.
an expression of disagreement or complaint: without a squeak of protest
4.

a formal notarial statement drawn up on behalf of a creditor and declaring that the debtor has dishonoured a bill of exchange or promissory note
the action of drawing up such a statement
a formal declaration by a taxpayer disputing the legality or accuracy of his assessment

5.
a statement made by the master of a vessel attesting to the circumstances in which his vessel was damaged or imperilled
6.
the act of protesting
7.
under protest, having voiced objections; unwillingly
verb (prəˈtɛst)
8.
when intr, foll by against, at, about, etc; when tr, may take a clause as object. to make a strong objection (to something, esp a supposed injustice or offence)
9.
(when transitive, may take a clause as object) to assert or affirm in a formal or solemn manner
10.
(when transitive, may take a clause as object) to put up arguments against; disagree; complain; object: “I’m okay,” she protested, he protested that it was not his turn to wash up
11.
(transitive) (mainly US) to object forcefully to: leaflets protesting Dr King’s murder
12.
(transitive) to declare formally that (a bill of exchange or promissory note) has been dishonoured