Zealot; follower (7)
I believe the answer is:
devotee
I believe this is a double definition.
'zealot' is the first definition.
(I've seen this in another clue)
'follower' is the second definition.
(I know that devotee is a type of follower)
(Other definitions for devotee that I've seen before include "Person who is utterly loyal and committed to someone" , "Big fan" , "One strongly interested in something" , "Keen admirer" , "An enthusiastic admirer and supporter" .)