Speak out against (8)
I believe the answer is:
denounce
'speak out against' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for denounce that I've seen before include "Accuse publicly" , "None cued (anag.)" , "Speak publicly against, censure" , "Speak violently against" , "Speak publicly against, having cue with no end" .)