Actors turn a deaf ear to it (5)
I believe the answer is:
aside
'actors turn' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'a deaf ear to it' is the wordplay.
'deaf ear' becomes 'side' (I can't justify this - if you can you should give a lot more credence to this answer).
'to it' says to put letters next to each other.
'a'+'side'='ASIDE'
Can you help me to learn more?
(Other definitions for aside that I've seen before include "Line spoken to theatre audience" , "Actors comment to his audience" , "kept in reserve" , "Line spoken to the audience of a play" , "Apart; incidental remark" .)