Advocate is a word that describes someone who supports or speaks in favor of a particular cause or idea. Some synonyms for advocate include champion, supporter, defender, ally, spokesperson, promoter, and proponent. A champion is a person who fights for a cause or idea. A supporter is someone who provides assistance to a person or organization. A defender is a person who defends something or someone against attack or criticism. An ally is a person who is on the same side as another. A spokesperson is someone who speaks on behalf of another. A promoter is someone who helps to popularize or publicize something. A proponent is a person who advocates for a particular idea or policy.