The capital of Latvia (4)
I believe the answer is:
riga
'the capital of latvia' is the definition.
('Riga' can be a synonym of 'capital of latvia')
This is the entire clue.
(Other definitions for riga that I've seen before include "Latvian port" , "Baltic capital city" , "port in Latvia" , "European capital" , "Fix a rig up here for the Latvians" .)