Quiet listener, is trim (5)
I believe the answer is:
shear
'trim' is the definition.
(shearing is a kind of trimming)
'quiet listener' is the wordplay.
'quiet' becomes 'sh'.
'listener' becomes 'ear' (I've seen this before).
'sh'+'ear'='SHEAR'
'is' is the link.
(Other definitions for shear that I've seen before include "Cut sheep's woll with large scissors" , "shave" , "Barber" , "Clip a sheep" , "Cut with clippers" .)