Down with evil! (3)
I believe the answer is:
ill
I believe this clue is a double definition.
'down' is the first definition.
(thesaurus)
'evil' is the second definition.
(thesaurus)
'with' is the link.
(Other definitions for ill that I've seen before include "Wicked" , "poor" , "trouble" , "Seasick" , "In short, the state of Chicago" .)