Proclaimed girl should be allowed to get message (6)
I believe the answer is:
letter
'message' is the definition.
(I know that letter is a type of grapheme)
'proclaimed girl should be allowed' is the wordplay.
I cannot quite see how this works, but
'allowed' could be 'let' (to let is to allow or permit) and 'let' is found within the answer.
The remaining letters 'ter' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'to get' acts as a link.
Can you help me to learn more?
(Other definitions for letter that I've seen before include "A written form of communication" , "Alphabetic character" , "Character of the alphabet" , "Epistle, missive" , "An alphabetic unit" .)