Reject revolutionary outcast (5)
I believe the answer is:
repel
'reject' is the definition.
(I've seen this before)
'revolutionary outcast' is the wordplay.
'revolutionary' is a reversal indicator.
'outcast' becomes 'leper' (leper is a kind of outcast).
'leper' reversed gives 'REPEL'.
(Other definitions for repel that I've seen before include "Beat back; cause disgust to" , "Nauseate" , "Drive back, rebuff" , "Drive back or disgust" , "Fill with distaste" .)