What are synonyms of zealous supporter?

Here are some synonyms for "zealous supporter", depending on the specific nuance you want to convey:

General:

* Advocate

* Champion

* Devotee

* Enthusiast

* Fanatic

* Follower

* Proponent

* Stalwart

* True believer

More intense:

* Diehard

* Evangelist

* Fanatic

* Zealot

More formal:

* Adept

* Adherent

* Protagonist

More informal:

* Backer

* Cheerleader

* Fan

The best synonym to use depends on the context of your writing. For example, "fanatic" might be appropriate for a very passionate supporter, while "advocate" might be better for someone who actively promotes a cause.