Possibly last round of French drink (7)
I believe the answer is:
decider
'possibly last round' is the definition.
The definition suggests a singular noun which matches the answer.
'of french drink' is the wordplay.
'of french' becomes 'de' ('of' in French).
'drink' becomes 'cider' (cider is a kind of drink).
'de'+'cider'='DECIDER'
Can you help me to learn more?
(Other definitions for decider that I've seen before include "Crucial final game" , "Ultimate goal" , "Important match" , "Extra period of play to settle a draw" , "It produces a winner after a drawn series" .)