As it happens, revolutionary is wrong (4)
I believe the answer is:
evil
'is wrong' is the definition.
(associated in meaning)
'as it happens revolutionary' is the wordplay.
'as it happens' becomes 'live' (as in live television).
'revolutionary' is a reversal indicator (letters revolve around).
'live' in reverse letter order is 'EVIL'.
(Other definitions for evil that I've seen before include "Morally wrong" , "Moral depravity" , "Wicked - sin" , "mischief" , "very naughty" .)