Quiet at the back, Ray (5)
I believe the answer is:
shaft
'ray' is the definition.
('shaft' can be a synonym of 'ray')
'quiet at the back' is the wordplay.
'quiet' becomes 'sh'.
'at' says to put letters next to each other.
'the back' becomes 'aft' (I've seen this before**).
'sh'+'aft'='SHAFT'
(Other definitions for shaft that I've seen before include "Mine access; handle" , "Vertical passage of mine" , "Vertical mine access" , "Handle - rod - passageway" , "Ray (of sunlight)" .)