Thick-skinned creature uttered sardonic refusal (5)
I believe the answer is:
rhino
'thick-skinned creature' is the definition.
(I've seen this in another clue)
'uttered sardonic refusal' is the wordplay.
I cannot quite see how this works, but
'refusal' could be 'no' (it's a no) and 'no' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for rhino that I've seen before include "Horned pachyderm" , "Fierce beast (abbr.)" , "In brief, large thick-skinned animal of Africa" , "old money?" , "Stumpy" .)