Notes, perhaps, that accountant is quiet (4)
I believe the answer is:
cash
'notes' is the definition.
(thesaurus)
'that accountant is quiet' is the wordplay.
'that accountant' becomes 'CA' (abbreviation for chartered accountant).
'is quiet' becomes 'sh' (both can be said to tell someone to be quiet).
'ca'+'sh'='CASH'
'perhaps' acts as a link.
(Other definitions for cash that I've seen before include "bread" , "Brass" , "notes, perhaps?" , ""Readies"" , "Ready money" .)