Something in post for landlord maybe (6)
I believe the answer is:
letter
I believe this clue is a double definition.
'something in post' is the first definition.
(letters are sent in the post)
'landlord maybe' is the second definition.
(I know that landlord is a type of letter)
'for' is the link.
(Other definitions for letter that I've seen before include "Character of the alphabet" , "Character - mail - landlord" , "It's one of twenty-six" , "Character; missive" , "Piece of correspondence" .)