Spy crushed revolutionary spirit (6)
I believe the answer is:
psyche
'spirit' is the definition.
(psyche is a kind of spirit)
'spy crushed revolutionary' is the wordplay.
'crushed' indicates an anagram.
'revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'spy' anagrammed gives 'psy'.
'psy'+'che'='PSYCHE'
(Other definitions for psyche that I've seen before include "Individuality" , "Immaterial part of a person" , "Princess beloved by Cupid" , "Analyse" , "A beautiful girl" .)