'Code' with inept resolution is cunning (9)
I believe the answer is:
deception
'cunning' is the definition.
(thesaurus)
'code with inept resolution' is the wordplay.
'with' is a charade indicator (letters next to each other).
'resolution' is an anagram indicator.
'code'+'inept'='codeinept'
'codeinept' with letters rearranged gives 'DECEPTION'.
'is' is the link.
(Other definitions for deception that I've seen before include "Duplicity" , "Trick" , "Fraud" , "Illusion" .)