Largest Caribbean island (4)
I believe the answer is:
cuba
'largest caribbean island' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cuba that I've seen before include "Large island discovered by Columbus, 1492" , "Island nation" , "Its capital is Havana" , "Caribbean island republic" , "Guantanamo Bay island" .)