Comedian's joke (3)
I believe the answer is:
gag
'comedian's joke' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for gag that I've seen before include "Part of stand-up routine" , "Muzzle or silence" , "Joke or muffler - a palindrome" , "Palindromic muxxle" , "Prevent from speaking freely" .)