The old neighbourhood? (4,4)
I believe the answer is:
grey area
'the old neighbourhood?' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
Can you help me to learn more?
(Other definitions for grey area that I've seen before include "doubtful situation" , "Ill-defined region" , "where work is inadequate" , "Matter about which there is no certainty" , "vague domain" .)