Renegade, traitor (8)
I believe the answer is:
turncoat
I believe this clue is a double definition.
'renegade' is the first definition.
(synonyms)
'traitor' is the second definition.
(I've seen this before)
(Other definitions for turncoat that I've seen before include "Traitor, defector" , "One betraying party" , "Traitor with reversed garment" , "Deserter to opposition" , "Traitor with inverted garment" .)