We hear a sighed utterance (5)
I believe the answer is:
aside
'utterance' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe there's a link between them I don't understand?
'we hear a sighed' is the wordplay.
'we' becomes 'a' (I can't explain this - if you can you should give a lot more credence to this answer).
'hear' shows a homophone (sound like).
'sighed' sounds like 'side'.
'a'+'side'='ASIDE'
Can you help me to learn more?
(Other definitions for aside that I've seen before include "Separately" , "remark, incidentally" , "(Turn) off main path" , "Remark not for hearing" , "private" .)