King, troublesome fellow, acquired knowledge (7)
I believe the answer is:
learned
'acquired knowledge' is the definition.
('learn' can be a synonym of 'acquire knowledge')
'king troublesome fellow' is the wordplay.
'king' becomes 'lear' (King Lear).
'troublesome fellow' becomes 'ned' (I can't explain this - if you can you should give a lot more credence to this answer).
'lear'+'ned'='LEARNED'
Can you help me to learn more?
(Other definitions for learned that I've seen before include "Picked up - well-read" , "Was taught" , "Highbrow" , "Gained knowledge" , "Wise, educated" .)