Not different from this America (4)
I believe the answer is:
same
'not different' is the definition.
('same' is the opposite to 'different')
'from this america' is the wordplay.
'from' says the answer is hidden in the clue.
'SAME' is hidden within 'this america'.
(Other definitions for same that I've seen before include "Ditto" , "Equal in amount or value" , "Identical, not different" , "uniform" , "Identical, unchanged" .)