A pro-claimer is someone who openly advocates for a particular cause, belief or ideology. Synonyms for this word include advocate, promoter, spokesperson, champion, supporter, evangelist, orator, messenger, or preacher. An advocate is someone who publicly supports a particular cause or idea. A promoter is a person who actively promotes or advances a particular idea or product. A spokesperson is someone who speaks on behalf of a particular organization or group. A champion is an individual who fiercely advocates for something. A supporter is someone who stands up for a particular cause or individual. An evangelist is someone who preaches or spreads the word about a particular religion or belief. Finally, a preacher is someone who gives religious sermons or speaks publicly about specific religious teachings.