Sally's comeback (7)
I believe the answer is:
riposte
This clue is a double definition.
'sally's' is the first definition.
(I've seen this before)
'comeback' is the second definition.
(I know that comeback can be written as riposte)
(Other definitions for riposte that I've seen before include "Rejoinder" , "Rejoin" , "Repartee; quick thrust (fencing)" , "Quick retort or return hit in fencing" , "Quick clever reply" .)