noun / adjective
adherent
ad-HEER-unt/ədˈhɪrənt/
Remaining firmly attached to something.
The campaign's adherent applauds the speaker and waves a matching pennant.

Etymology
An adherent is figuratively someone “sticking to” a leader, cause, or belief. Physical clinging supplies the image for loyalty and continued support.
In context
the word Muslim is the title for somebody who's an adherent of the religion so somebody who follows the religion is a Muslim
More examples
- The candidate's adherents gather outside the meeting hall.
- An adherent layer of clay covers the buried pottery.
- She remains adherent to the principles she learned as a student.
Forms
adherent · adherents
adherence noun — Firm attachment or faithful observance of something.