Vilifies (6)
I believe the answer is:
smears
'vilifies' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for smears that I've seen before include "Attempts to damage a reputation" , "may be examined in the lab." , "Slanderous defamations" , "False attacks on someone's good name" , "Spreads with dirty or greasy substance" .)