Jamaican citrus (4)
I believe the answer is:
ugli
'jamaican citrus' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ugli that I've seen before include "Hybrid of tangerine and grapefruit" , "Jamaican form of 6" , "Large juicy fruit with thick wrinkled skin" , "West Indian citrus fruit" , "Mottled tangelo hybrid" .)