Short witty remark (7)
I believe the answer is:
epigram
'short witty remark' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for epigram that I've seen before include "short satirical poem" , "Concise witty remark" , "Quip, witty saying" , "A short witty saying" , "Short witty remark" .)