Chap reported letters (4)
I believe the answer is:
'letters' is the definition.
(I've seen this in another clue)
'chap reported' is the wordplay.
'chap' becomes 'male' (chap can mean a man).
'reported' indicates a 'sounds like' (homophone) clue.
'male' sounds like 'MAIL'.
(Other definitions for mail that I've seen before include "some self-defence material" , "Post in America" , "Letters and parcels" , "Chain armour" , "letter?" .)