Refusal, in any case, to be a nuisance (5)
I believe the answer is:
annoy
'to be a nuisance' is the definition.
(I've seen this before)
'refusal in any' is the wordplay.
'refusal' becomes 'no'.
'in' is an insertion indicator.
'no' going within 'any' is 'ANNOY'.
'case' is the link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for annoy that I've seen before include "get angry" , "Displease" , "be a nuisance" , "eat" , "trouble" .)