City where mail goes astray (4)
I believe the answer is:
lima
'city' is the definition.
(Lima is an example)
'mail goes astray' is the wordplay.
'goes astray' indicates anagramming the letters.
'mail' is an anagram of 'LIMA'.
'where' acts as a link.
(Other definitions for lima that I've seen before include "Mail it to Peruvian city" , "Peruvian capital" , "Mail to Peru'd capital" , "distant city" , "city (like 22)" .)