Fool's intelligence (4)
I believe the answer is:
dope
This clue is a double definition.
'fool's' is the first definition.
(thesaurus)
'intelligence' is the second definition.
(thesaurus)
(Other definitions for dope that I've seen before include "Drugs for a dimwit" , "Fool - model aeroplane varnish" , "Dolt -- drug" , "Sucker" , "Idiot; information" .)