Island able to turn (4)
I believe the answer is:
elba
'island' is the definition.
(Italian island)
'able to turn' is the wordplay.
'to turn' shows that the letters should be reversed in order.
'able' reversed gives 'ELBA'.
(Other definitions for elba that I've seen before include "Abel (anag)" , "Island off Italy" , "Exile isle for Napoleon" , "Italian island" , "Island off Tuscany" .)