Person crossing English city (5)
I believe the answer is:
seoul
'city' is the definition.
(I know that Seoul is a national capital)
'person crossing english' is the wordplay.
'person' becomes 'soul' (synonyms).
'crossing' means one lot of letters goes inside another (to cross can mean to go over or around).
'english' becomes 'E' (abbreviation).
'soul' placed around 'e' is 'SEOUL'.
(Other definitions for seoul that I've seen before include "South Korea capital" , "19 [EASTERN] capital" , "Olympic venue" , "Capital city" , "Asian capital" .)