Smart city accommodates a race (5)
I believe the answer is:
natty
'smart' is the definition.
(I've seen this in another clue)
'city accommodates a race' is the wordplay.
'city' becomes 'NY' (short for New York).
'accommodates' is an insertion indicator.
'race' becomes 'tt'.
'a'+'tt'='att'
'ny' placed around 'att' is 'NATTY'.
(Other definitions for natty that I've seen before include "Informally neat and well-dressed" , "Smart, spruce" , "Smart, fashionable (colloq.)" , "Flashily smart" , "Stylishly dressed" .)