Detective facing tough neighbourhood (8)
I believe the answer is:
district
'neighbourhood' is the definition.
(thesaurus)
'detective facing tough' is the wordplay.
'detective' becomes 'di' (Detective Inspector abbreviation).
'facing' is a charade indicator (letters next to each other).
'tough' becomes 'strict' (I've seen this before).
'di'+'strict'='DISTRICT'
(Other definitions for district that I've seen before include "Area (of a town/city)" , "Area of town/country" , "Territorial division" , "A quarter" , "Area of a town or city" .)