Rene's wrong to scoff! (5)
I believe the answer is:
sneer
'scoff' is the definition.
(I've seen this before)
'rene's wrong' is the wordplay.
'wrong' indicates an anagram.
'renes' with letters rearranged gives 'SNEER'.
'to' is the link.
(Other definitions for sneer that I've seen before include "Taunt" , "Show contempt with scornful expression or words" , "Be derisive; Sheridan's Critic" , "Derisive remark" , "Contemptuous or mocking smile" .)