The capital of Libya (7)
I believe the answer is:
tripoli
'the capital of libya' is the definition.
('Tripoli' can be a synonym of 'capital of libya')
This is all the clue.
(Other definitions for tripoli that I've seen before include "where there's been regime change" , "City in Libya - city in Lebanon" , "North African port" , "Libyan city" , "city on the Mediterranean" .)