Troublemaker takes sword to tree with energy (9)
I believe the answer is:
firebrand
'troublemaker' is the definition.
(thesaurus)
'sword to tree with energy' is the wordplay.
'sword' becomes 'brand' ('brand' can be a synonym of 'sword').
'to' says to put letters next to each other (I've seen this in other clues).
'tree with' becomes 'fir' (fir is a kind of tree. I am not sure about the 'with' bit.**).
'energy' becomes 'e' (physics symbol as in E=mci).
'fir'+'e'='fire'
'brand' after 'fire' is 'FIREBRAND'.
'takes' acts as a link.
Can you help me to learn more?
(Other definitions for firebrand that I've seen before include "Energetic person often fomenting trouble" , "One who stirs up trouble" , "Agitator" , "Rabble-rouser" , "Troublemaker" .)