Ask for quiet conduct (5)
I believe the answer is:
plead
'ask for' is the definition.
(thesaurus)
'quiet conduct' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'conduct' becomes 'lead' ('lead' can be a synonym of 'conduct').
'p'+'lead'='PLEAD'
(Other definitions for plead that I've seen before include "Supplicate" , "Present an argument in court" , "Offer something in excuse!" , "Argue (a position in court)" , "Make an emotional appeal" .)