Island of Napoleon's exile (4)
I believe the answer is:
elba
'island of napoleon's exile' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for elba that I've seen before include "Island in the Med" , "Island of Napoleon's exile in 1814-15" , "Where emperor was confined" , "Bale out of the Mediterranean island" , "Island of imperial exile" .)