Bon mot (7)
I believe the answer is:
epigram
'bon mot' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for epigram that I've seen before include "Sally perhaps" , "Concise witty saying" , "Bon mot" , "Pithy remark - grim ape (anag)" , "Brief witty saying" .)