Grounation Day celebrant (5)
I believe the answer is:
rasta
'grounation day celebrant' 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 "worshipper from Jamaica" , "Disciple" , "worshipper of Haile Selassie" , "Jamaican believer" , "A certain believer" .)