Young animal going over a West Indian island (4)
I believe the answer is:
cuba
'west indian island' is the definition.
(I've seen this before)
'young animal going over a' is the wordplay.
'young animal' becomes 'cub' (I've seen this before).
'going over' means one lot of letters go next to another.
'cub'+'a'='CUBA'
(Other definitions for cuba that I've seen before include "Island nation" , "Largest Caribbean island" , "Guantanamo Bay location" , "Castro's country" , "Hemingway's stamping-ground" .)