Firm not exactly quiet, finding money (4,4)
I believe the answer is:
hard cash
'money' is the definition.
(I've seen this before)
'firm not exactly quiet' is the wordplay.
'firm' becomes 'hard' ('hard' can be similar in meaning to 'firm').
'not exactly' becomes 'ca' (circa).
'quiet' becomes 'sh'.
'hard'+'ca'+'sh'='HARD CASH'
'finding' acts as a link.
(Other definitions for hard cash that I've seen before include "Not plastic!" , "Coins and banknotes - not a cheque" , "Ready money" , "Coins and notes, not cheques or promises" .)