Driving out evil energy, replacing nothing troubling (10)
I believe the answer is:
exercising
'nothing troubling' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'driving out evil energy replacing' is the wordplay.
I cannot really understand how this works, but
'evil' could be 'sin' (synonyms) and 'sin' is located in the answer.
'energy' could be 'e' (physics symbol as in E=mc2) and 'e' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for exercising that I've seen before include "activity in gym?" , "training" .)