Three couples send rude message — and in French (6)
I believe the answer is:
sextet
'three couples' is the definition.
(I've seen this before)
'message and in french' is the wordplay.
'message' becomes 'sext' (I have seen 'Explicit message' mean 'sext' so perhaps 'message' could also mean 'sext').
'and' means one lot of letters go next to another.
'in french' becomes 'et' (I've seen this in other clues).
'sext'+'et'='SEXTET'
'send rude' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for sextet that I've seen before include "Three couples" , "Group of six instruments or voices" , "Musical work" , "Group of six performers" , "Half-dozen in a group" .)