Groaner (3)
I believe the answer is:
pun
'groaner' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pun that I've seen before include "Double entendre" , "Humorous wordplay" , "A play on words, may be funny" , "Bit of paronomasia; witticism" , "A play on words, not really wit" .)