Remain idle (4)
I believe the answer is:
rest
I believe this is a double definition.
'remain' is the first definition.
('rest' can be a synonym of 'remain')
'idle' is the second definition.
(thesaurus)
(Other definitions for rest that I've seen before include "Lie down" , "'Relax, pause from work (4)'" , "Calm" , "Others; cease work" , "Support for putting things on" .)