Silent songbird trapping bill (5)
I believe the answer is:
tacit
'silent' is the definition.
(I know that silent can be written as tacit)
'songbird trapping bill' is the wordplay.
'songbird' becomes 'tit' (tit is a type of songbird).
'trapping' is an insertion indicator.
'bill' becomes 'ac' (short for account).
'tit' placed around 'ac' is 'TACIT'.
(Other definitions for tacit that I've seen before include "Silently understood" , "Understood without being directly expressed" , "Implied but not directly expressed" , "without speaking" , "Respect, admiration" .)