Revolutionary looking angry? (3)
I believe the answer is:
red
This clue is a double definition.
'revolutionary' is the first definition.
(informal term for communist)
'looking angry?' is the second definition.
(someone may go red when angry)
(Other definitions for red that I've seen before include "Colour of garnets" , "Type of wine" , "Carmine" , "Merchant flag" , "Very angry, seeing this" .)