Funny person's nonsense I accepted (4)
I believe the answer is:
riot
'funny person's' is the definition.
(I've seen this in another clue)
'nonsense i accepted' is the wordplay.
'nonsense' becomes 'rot' (rot can mean nonsense or rubbish).
'accepted' means one lot of letters goes inside another.
'rot' placed around 'i' is 'RIOT'.
(Other definitions for riot that I've seen before include "A public affray or disturbance" , "Public disorder" , "Violent disturnance of the peace (by crowd)" , "Civil unrest" , "A wild public affray" .)