Hesitation entering a US city after smart tricks (9)
I believe the answer is:
chicanery
'tricks' is the definition.
(I have seen 'legal tricks' mean 'chicanery' so perhaps 'tricks' could also mean 'chicanery')
'hesitation entering a us city after smart' is the wordplay.
'hesitation' becomes 'er' (sound made while hesitating - um, er).
'entering' means one lot of letters goes inside another.
'us city' becomes 'NY' (abbreviation for New York).
'after' is a charade indicator (letters next to each other).
'smart' becomes 'chic' (both can mean stylish).
'a'+'ny'='any'
'er' inserted into 'any' is 'anery'.
'anery' after 'chic' is 'CHICANERY'.
(Other definitions for chicanery that I've seen before include "legal tricks" , "Use of deception for gain" , "Double-dealing" , "Sharp practice" , "dishonest practices" .)