Sophisticated girl seen within city limits (6)
I believe the answer is:
classy
'sophisticated' is the definition.
(I've seen this in another clue)
'girl seen within city limits' is the wordplay.
'girl' becomes 'lass' (lass can informally mean a girl).
'seen within' indicates putting letters inside.
'limits' says to hollow out the word (remove centre letters).
'city' with its middle removed is 'cy'.
'lass' inserted inside 'cy' is 'CLASSY'.
(Other definitions for classy that I've seen before include "Stylish (slang)" , "Informally stylish and superior" , "Elegant and fashionable, posh" , "Sophisticated, stylish" , "showing style ..." .)