Joke; a witticism (4)
I believe the answer is:
jest
I believe this is a double definition.
'joke' is the first definition.
(synonyms)
'a witticism' is the second definition.
(jest is a kind of witticism)
(Other definitions for jest that I've seen before include "fun" , "Joke, fool about" , "In ____, playfully" , "Ridicule" , "Piece of humour" .)