Country with revolutionary enthusiast is the reverse of excellent (7)
I believe the answer is:
tunisia
'country' is the definition.
(Tunisia is an example)
'revolutionary enthusiast is the reverse of excellent' is the wordplay.
'revolutionary' is a reversal indicator.
'enthusiast' becomes 'nut' (I've seen this before).
'the reverse of' is a reversal indicator.
'excellent' becomes 'ai'.
'nut' reversed gives 'tun'.
'ai' in reverse letter order is 'ia'.
'tun'+'is'+'ia'='TUNISIA'
'with' is the link.
(Other definitions for tunisia that I've seen before include "country-style" , "North African republic" , "Country between Algeria/Libya" , "African state" , "N African country in which ancient Carthage lies" .)