Fool corruptly dealt with cop (8)
I believe the answer is:
clodpate
'fool' is the definition.
(thesaurus)
'corruptly dealt with cop' is the wordplay.
'corruptly' is an anagram indicator.
'with' says to put letters next to each other.
'dealt' put after 'cop' is 'copdealt'.
'copdealt' with letters rearranged gives 'CLODPATE'.
(Other definitions for clodpate that I've seen before include "Fool" , "Dimwit" .)