β Guevara (3)
I believe the answer is:
che
'guevara' is the definition.
(revolutionary Che Guevara)
This is the entire clue.
(Other definitions for che that I've seen before include "Nickname of Ernesto Guevara" , "-- Guevara, revolutionary" , "First person" , "Fighter" , "- Guevara, guerrilla" .)