Place accepting knight's funny routine (4)
I believe the answer is:
skit
'funny routine' is the definition.
'place accepting knight's' is the wordplay.
'place' becomes 'sit' (sitting is a kind of placing**).
'accepting' indicates putting letters inside.
'knight' becomes 'k'.
'sit' placed around 'k' is 'SKIT'.
(Other definitions for skit that I've seen before include "Comic sketch" , "Opportunity to take off" , "that may be produced by 19 [PARODIST]" , "A piece of humorous mimicry" , "Comedy routine" .)