Join in revolution, deposing leader with initiative (12)
I believe the answer is:
enterprising
'deposing leader with initiative' is the definition.
I can't judge whether this definition defines the answer.
'join in revolution' is the wordplay.
'join in' becomes 'enter' (I've seen this before).
'revolution' becomes 'prising' (I can't justify this - if you can you should believe this answer much more).
'enter'+'prising'='ENTERPRISING'
Can you help me to learn more?
(Other definitions for enterprising that I've seen before include "daring" , "Go ahead" , "Entrepreneurial" , "Showing initiative" , "Adventurous, resourceful" .)