Exotic agora: one place you can’t enter (2-2,4)
I believe the answer is:
no-go area
'place you can't enter' is the definition.
(somewhere you cannot go)
'exotic agora one' is the wordplay.
'exotic' is an anagram indicator (an unusual form of the letters).
'agora'+'one'='agoraone'
'agoraone' is an anagram of 'NO-GO AREA'.
(Other definitions for no-go area that I've seen before include "Zone where access is barred or risky" , "District into which entry is dangerous or forbidden" , "Off-limits district" , "Place not to be entered" , "Part of city off-limits" .)