Willingly left member with account to pay finally (6)
I believe the answer is:
legacy
'willingly left' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'member with account to pay finally' is the wordplay.
'member' becomes 'leg' (member can mean a limb).
'with' is a charade indicator (letters next to each other).
'account' becomes 'ac' (abbreviation for account).
'to' is a charade indicator (letters next to each other).
'finally' says to take the final letters.
The final letter of 'pay' is 'y'.
'leg'+'ac'+'y'='LEGACY'
Can you help me to learn more?
(Other definitions for legacy that I've seen before include "Hand-me-down" , "One inherited" , "Birthright" , "That which is handed down by a predecessor" , "A bequest, something left in a will" .)