Quiet section overheard (5)
I believe the answer is:
peace
'quiet' is the definition.
(I've seen this before)
'section overheard' is the wordplay.
'section' becomes 'piece' (I've seen this before).
'overheard' shows a homophone (sound like).
'piece' is a homophone of 'PEACE'.
(Other definitions for peace that I've seen before include "Caught" , "Calm, serenity" , "an answer to all clues, initially" , "Calm, tranquility" , "Calmness" .)