Messenger cut short one final message (5)
I believe the answer is:
This clue could be a double definition.
'messenger cut' is the first definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'one final message' is the second definition.
(I've seen this before)
'short' is the link.
Can you help me to learn more?
(Other definitions for envoi that I've seen before include "Brief stanza concluding a poem" , "Concluding part of poem or book" , "Concluding lines" , "Second Hebrew letter" , "Short concluding stanza" .)