Mostly genuine over the German University post (6)
I believe the answer is:
reader
'university post' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'mostly genuine over the german' is the wordplay.
'mostly' means to remove the last letter (most but not all of the word).
'genuine' becomes 'real' (associated in meaning).
'over' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'the german' becomes 'der' ('the' in German).
'real' with its final letter taken away is 'rea'.
'rea'+'der'='READER'
Can you help me to learn more?
(Other definitions for reader that I've seen before include "Publisher's selector" , "member of the university" , "Person studying a book" , "University academic" , "Text book -- red ear (anag)" .)