Danger zone (2-2,4)
I believe the answer is:
no-go area
'danger zone' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for no-go area that I've seen before include "Off-limits district" , "Out-of-bounds zone" , "Region where entry is dangerous, impossible, or forbidden" , "Zone which one must not enter" , "Zone where access is barred or risky" .)