Revolutionary goes beyond mark (4)
I believe the answer is:
spot
'mark' is the definition.
(spotting is a kind of marking)
'revolutionary goes beyond' is the wordplay.
'revolutionary' shows that the letters should be reversed in order.
'goes beyond' becomes 'tops' ('top' can be a synonym of 'go beyond').
'tops' back-to-front is 'SPOT'.
(Other definitions for spot that I've seen before include "jam > stain" , "Discern - mark" , "See; round mark" , "Catch sight of - pimple" , "Espy; mark" .)