Stop working in retreat (6)
I believe the answer is:
retire
I believe this clue is a double definition.
'stop working' is the first definition.
(retiring from work)
'retreat' is the second definition.
(as in retiring for the night)
'in' acts as a link.
(Other definitions for retire that I've seen before include "Withdraw - give up work - go to bed" , "Stop climbing the ladder" , "call it a day" , "end occupation" , "Pull back" .)