A US city individual, no matter who (6)
I believe the answer is:
anyone
'no matter who' is the definition.
(I've seen this before)
'a us city individual' is the wordplay.
'us city' becomes 'NY' (short for New York).
'individual' becomes 'one' (an individual is one person).
'a'+'ny'+'one'='ANYONE'
(Other definitions for anyone that I've seen before include "Animal-hunting trip" , "No particular person" , "A person in general" , "Has ...here seen Kelly (music hall song)" , "Whosoever" .)