Dope the dog (4)
I believe the answer is:
mutt
I believe this clue is a double definition.
'dope' is the first definition.
(thesaurus)
'dog' is the second definition.
(mutt is a kind of dog)
'the' acts as a link.
(Other definitions for mutt that I've seen before include "Mongrel dog - foolish person" , "Mongrel - fool" , "Chump" , "far from best in show?" , "Setter perhaps" .)