Here are some other words you could use depending on the context:
* Tagapamagitan - This is the most general and accurate translation.
* Tagapagtaguyod - This word implies someone who actively advocates for another person.
* Tagapag-usap - This word implies someone who speaks on behalf of another person.
* Tagapagtanggol - This word implies someone who protects or defends another person.
The best word to use will depend on the specific context of your sentence.