Tough revolutionary essentially spewing poppycock (5)
I believe the answer is:
chewy
'tough' is the definition.
(similar in meaning)
'revolutionary essentially spewing poppycock' is the wordplay.
'revolutionary' becomes 'Che' (Che Guevara).
'essentially' indicates the central letters.
'poppycock' becomes 'y' (I can't explain this - if you can you should believe this answer much more).
The central letter of 'spewing' is 'w'.
'che'+'w'+'y'='CHEWY'
Can you help me to learn more?
(Other definitions for chewy that I've seen before include "Tough to masticate" , "Taking much mastication" , "Requiring mastication, like toffee say" , "Hard to eat" , "With a texture like toffee" .)