Treat corns with contempt (5)
I believe the answer is:
scorn
'contempt' is the definition.
(I know that contempt can be written as scorn)
'treat corns' is the wordplay.
'treat' is an anagram indicator.
'corns' anagrammed gives 'SCORN'.
'with' acts as a link.
(Other definitions for scorn that I've seen before include "Disgust" , "Extreme contempt" , "Look at with disdain" , "Disdain or derision" , "Slight" .)