Worshipper of Jah (5)
I believe the answer is:
rasta
'worshipper of jah' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for rasta that I've seen before include "Jamaican cult member" , "Follower of Rastafarianism" , "A certain believer" , "One following religion" , "Jamaican cultist" .)