The capital of Greece (6)
I believe the answer is:
athens
'the capital of greece' is the definition.
('Athens' can be a synonym of 'capital of greece')
This is the entire clue.
(Other definitions for athens that I've seen before include "Hasten to the Hellenic city" , "City of the Parthenon" , "Hasten to Greece" , "Hasten (anag) -- capital city" , "Mediterranean capital" .)