Stabbed by blade, revolutionary howled (6)
I believe the answer is:
roared
'howled' is the definition.
('roar' can be a synonym of 'howl')
'stabbed by blade revolutionary' is the wordplay.
'stabbed by' means one lot of letters goes inside another (inserted letters stab into the word).
'blade' becomes 'oar' (blade is the word for oar in competitive rowing).
'revolutionary' becomes 'red' (red can informally mean communist).
'oar' placed inside 'red' is 'ROARED'.
(Other definitions for roared that I've seen before include "Yelled" , "Made long loud sound like lion" , "Bellowed, thundered" .)