Discharge an account and leave (6)
I believe the answer is:
acquit
'discharge' is the definition.
(to free from legal charges)
'an account and leave' is the wordplay.
'an account' becomes 'ac' (abbreviation for account).
'and' is a charade indicator (letters next to each other).
'leave' becomes 'quit' (synonyms).
'ac'+'quit'='ACQUIT'
(Other definitions for acquit that I've seen before include "Declare to be innocent of a crime" , "Free (from charge)" , "Group of families" , "Let off" , "Exculpate" .)