Mail; characters (7)
I believe the answer is:
letters
This clue is a double definition.
'mail' is the first definition.
(I've seen this in another clue)
'characters' is the second definition.
(letter is a kind of character)
(Other definitions for letters that I've seen before include "Literary culture" , "Characters" , "eg E G" , "Correspondence" , "providing digs?" .)