Revolutionary brew of beer by a beginner (5)
I believe the answer is:
rebel
'revolutionary' is the definition.
(rebel is a kind of revolutionary)
'brew of beer by a beginner' is the wordplay.
'brew of' indicates anagramming the letters (I've seen this in other clues).
'by' means one lot of letters go next to another.
'a beginner' becomes 'L' (as in a learner driver with L-plates on their car).
'beer' anagrammed gives 'rebe'.
'rebe'+'l'='REBEL'
(Other definitions for rebel that I've seen before include "One who rises up" , "Refuse orders" , "Oppose authority" , "Insurgent, mutineer" , "One who opposes the powerful" .)