Restricted zone (2-2,4)
I believe the answer is:
no-go area
'restricted zone' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for no-go area that I've seen before include "Off-limits district" , "It's taboo to enter" , "Prohibited zone" , "Forbidden zone" , "Place where entry is dangerous or forbidden" .)