Disciple of Haile Selassie, informally (5)
I believe the answer is:
rasta
(Other definitions for rasta that I've seen before include "Sectarian of Jamaican origin (colloq.)" , "Jamaican cult follower (informally)" , "worshipper of Haile Selassie" , "Jamaican cultist" , "Jamaican believer" .)