Suit worn around northern city (5)
I believe the answer is:
tunis
'city' is the definition.
(I know that Tunis is a national capital)
'suit worn around northern' is the wordplay.
'worn' indicates an anagram (worn can mean damaged).
'around' is an insertion indicator.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'suit' is an anagram of 'tuis'.
'tuis' enclosing 'n' is 'TUNIS'.
(Other definitions for tunis that I've seen before include "N African port" , "Capital of a republic in north Africa" , "I stun (anag) - port and capital" , "Mediterranean capital and port" , "Tom, Dick or Harry" .)