Despicable criminal in house (7)
I believe the answer is:
heinous
'despicable' is the definition.
(thesaurus)
'criminal in house' is the wordplay.
'criminal' indicates an anagram.
'in'+'house'='inhouse'
'inhouse' with letters rearranged gives 'HEINOUS'.
(Other definitions for heinous that I've seen before include "Shockingly wicked" , "Diabolic" , "Execrable" , "Very wicked, maybe in-house" , "Extremely wicked" .)