Quietly be indebted to Greek character and work for energetic person (10)
I believe the answer is:
powerhouse
'energetic person' is the definition.
(synonyms)
'quietly be indebted to greek character and work for' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'be indebted to' becomes 'owe' (I've seen this in another clue).
'greek character' becomes 'rho' (letter of the Greek alphabet).
'and' is a charade indicator (letters next to each other).
'work for' becomes 'use' (I can't explain this - if you can you should believe this answer much more).
'p'+'owe'+'rho'+'use'='POWERHOUSE'
Can you help me to learn more?
(Other definitions for powerhouse that I've seen before include "Dynamo" , "Energetic person" , "Person with great energy" , "Remarkably forceful person" , "Dynamic person" .)