Despises saints penning hackneyed stuff (6)
I believe the answer is:
scorns
'despises' is the definition.
('scorn' can be a synonym of 'despise')
'saints penning hackneyed stuff' is the wordplay.
'saints' becomes 'ss' (an abbreviation for saint written twice).
'penning' is an insertion indicator.
'hackneyed stuff' becomes 'corn' (as in cliched or corny material).
'ss' placed around 'corn' is 'SCORNS'.
(Other definitions for scorns that I've seen before include "Rejects with contempt" , "Has contempt for, disdains" , "Has or shows contempt for" , "Looks down on" , "Holds in contempt" .)