Revolutionary - or master traitor? (5)
I believe the answer is:
marat
'revolutionary' is the definition.
(French revolutionary Jean-Paul Marat)
'master traitor?' is the wordplay.
'master' becomes 'ma' (Master of Arts).
'traitor?' becomes 'rat' (rat can mean a treacherous person).
'ma'+'rat'='MARAT'
'or' acts as a link.
(Other definitions for marat that I've seen before include "French revolutionary killed in his bath" , "Charlotte Corday victim" , "Jean Paul, French revolutionary, murdered in his bath" , "Charlotte Corday murdered him in his bath" , "murdered radical" .)