Account with something charged, a large amount (7)
I believe the answer is:
billion
'a large amount' is the definition.
(large number)
'account with something charged' is the wordplay.
'account' becomes 'bill' (billing is a kind of accounting).
'with' says to put letters next to each other.
'something charged' becomes 'ion'.
'bill'+'ion'='BILLION'
(Other definitions for billion that I've seen before include "One thousand million" , "1,000,000,000" , "A large number" , "One followed by nine zeros" .)