Retort; reply (7)
I believe the answer is:
riposte
I believe this is a double definition.
'retort' is the first definition.
(synonyms)
'reply' is the second definition.
(riposte is a kind of reply)
(Other definitions for riposte that I've seen before include "Fencer's counterattack" , "Sharp answer" , "Quick retort or return thrust in fencing" , "Snappy comeback" , "Witty retort" .)