Metal bar from island (5)
I believe the answer is:
cuban
'from island' is the definition.
(from Cuba)
'metal bar' is the wordplay.
'metal' becomes 'Cu' (chemical symbol for copper).
'bar' becomes 'ban' (I've seen this before).
'cu'+'ban'='CUBAN'
(Other definitions for cuban that I've seen before include "Caribbean" , "Nationality of citizen of Havana" , "islander" , "From Castro's island" , "Citizen of Castro's country" .)