pro·tes·tor^[1]

affirm
bear witness
to declare in public

Synonyms for protestor

arbitro – arbitrate, bear witness, judge, to witness
arbitror – arbitrate, bear witness, judge, to witness
autumo – affirm, believe, to assert
firmo – affirm, encourage, maintain, make firm, secure, strengthen, to assert, to make lasting
protesto – affirm, bear witness, to declare in public
retineo – affirm, detain, keep, maintain, not let go, restrain, to hold back, to remember

Similar to protestor

protesto – affirm, bear witness, to declare in public
proditor – betrayer, traitor
procurator – agent, bailiff, manager
progenitor – ancestor, founder of a family
proavus – great
probabilis – credible
probabiliter – with credibility
probatur – examine, from probo, test, to judge
probatus – approved
probitas – honesty, liberality, probity, uprightness