Monstrous guise ogre adopted (9)
I believe the answer is:
egregious
'adopted' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'monstrous guise ogre' is the wordplay.
'monstrous' indicates an anagram.
'guise'+'ogre'='guiseogre'
'guiseogre' with letters rearranged gives 'EGREGIOUS'.
Can you help me to learn more?
(Other definitions for egregious that I've seen before include "Outstandingly bad" , "Outstandingly villainous" , "Flagrant; appalling" , "Insufferable" , "Shocking" .)