Feature on a country (5)
I believe the answer is:
china
'country' is the definition.
(I know that China is a great power)
'feature on a' is the wordplay.
'feature' becomes 'chin' (facial feature).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'chin'+'a'='CHINA'
(Other definitions for china that I've seen before include "Country; friend (slang)" , "Country - crockery" , "Modern name for old Cathay" , "Cathay was its archaic name" , "Household ceramics" .)