Sophisticated earlier city (7)
I believe the answer is:
chicago
'city' is the definition.
(I know that Chicago is a city)
'sophisticated earlier' is the wordplay.
'sophisticated' becomes 'chic' (I've seen this in another clue).
'earlier' becomes 'ago' (I've seen this in another clue).
'chic'+'ago'='CHICAGO'
(Other definitions for chicago that I've seen before include "Al Capone's city" , "1970s' John Kander/Fred Ebb musical" , "Port on Lake Michigan" , "Type of bridge" , "US city - musical featuring All That Jazz" .)