Great revolutionary circus feature? (3,3)
I believe the answer is:
big top
'circus feature?' is the definition.
(I've seen this in another clue)
'great revolutionary' is the wordplay.
'great' becomes 'big' (similar in meaning).
'revolutionary' becomes 'top' (I can't justify this - if you can you should believe this answer much more).
'big'+'top'='BIG TOP'
Can you help me to learn more?
(Other definitions for big top that I've seen before include "'Main circus tent (3,3)'" , "needed by Mae West, for one?" , "performance in The Ring" , "entertainment centre" , "Circus venue" .)