Prompt and quiet staff (4)
I believe the answer is:
prod
'prompt' is the definition.
(thesaurus)
'quiet staff' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'staff' becomes 'rod' (I've seen this before).
'p'+'rod'='PROD'
'and' is the link.
(Other definitions for prod that I've seen before include "Poke, stimulate into action" , "Induce action (with stick etc?)" , "Incite to action (with a stick?)" , "Give a reminder" , "Poke; reminder" .)