Fancy Prussia suppressing a republic (6)
I believe the answer is:
cyprus
'a republic' is the definition.
(Cyprus is a republic)
'fancy prussia suppressing' is the wordplay.
'suppressing' indicates the answer is hidden within the clue (the answer is suppressed or covered by the clue).
'CYPRUS' is hidden in the letters of 'fancy prussia'.
(Other definitions for cyprus that I've seen before include "Large East Mediterranean island" , "Divided Mediterranean island" , "Island - legendary home of Aphrodite" , "Mediterranean island, capital Nicosia" , "Divided Med. island" .)