Prisoner sporting black eye, a wealthy Greek perhaps (9)
I believe the answer is:
shipowner
'a wealthy greek perhaps' is the definition.
(shipping is a major part of the Greek economy)
'prisoner sporting black eye' is the wordplay.
'prisoner' becomes 'POW' (prisoner of war).
'sporting' means one lot of letters goes inside another (inserted letters wear or 'sport' others).
'black eye' becomes 'shiner' (synonyms).
'pow' inserted inside 'shiner' is 'SHIPOWNER'.
(Other definitions for shipowner that I've seen before include "Crafty proprietor" , "Onassis, say" , "I've secured brig" , "man over the line" .)