Comic knees-up (5)
I believe the answer is:
beano
'comic' is the definition.
(The Beano is a British comic)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for beano that I've seen before include "Enjoyable party" , "rowdy festivity" , "Celebration" , "Function" , "Comic - party" .)