Old Greek city-state (6)
I believe the answer is:
sparta
I believe this is a double definition.
'old greek city' is the first definition.
(I've seen this before)
'state' is the second definition.
(I know that Sparta is a state)
(Other definitions for sparta that I've seen before include "in ancient Greece" , "austere place" , "Ancient Greek city state" , "Enemy of Athens?" , "Ancient Greek city, capital of Laconia" .)