Criminal don's cruel rogue (9)
I believe the answer is:
scoundrel
'rogue' is the definition.
(both can mean a dishonourable person)
'criminal don's cruel' is the wordplay.
'criminal' indicates anagramming the letters.
'dons'+'cruel'='donscruel'
'donscruel' with letters rearranged gives 'SCOUNDREL'.
(Other definitions for scoundrel that I've seen before include "Cad" , "Knave" , "Bounder" , "Villain" , "Person that's low" .)