Anguish of the French couple? (7)
I believe the answer is:
despair
'anguish' is the definition.
(thesaurus)
'of the french couple?' is the wordplay.
'of the french' becomes 'des' ('of the' in French).
'couple?' becomes 'pair' ('pair' can be a synonym of 'couple').
'des'+'pair'='DESPAIR'
(Other definitions for despair that I've seen before include "Hopeless" , "The feeling that nothing will turn out well" , "Feeling of hopelessness" , "Give up hope" , "sort of counsel?" .)