Neglected neighborhood (4)
I believe the answer is:
slum
'neglected neighborhood' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for slum that I've seen before include "Squalid and overcrowded urban area" , "Squalid neighbourhood" , "Squalid, overcrowded dwelling" , "Over-crowded run-down city area" , "Poor-quality accommodation" .)