Revolutionary involved in butchery (3)
I believe the answer is:
che
'revolutionary' is the definition.
(Che Guevara the Marxist revolutionary)
'involved in butchery' is the wordplay.
'involved in' indicates the answer is hidden within the clue.
'CHE' can be found hidden inside 'butchery'.
(Other definitions for che that I've seen before include "Fighter" , "Nickname of Ernesto Guevara" , "First person" , "- Guevara, Marxist" , "-- Guevara, revolutionary" .)