New York City borough (9)
I believe the answer is:
manhattan
'new york city borough' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for manhattan that I've seen before include "intoxicating drink" , "New York City borough" , "NY borough" , "Cocktail of whiskey and sweet vermouth" , "Island of New York - cocktail" .)