Supports when one isn't working (5)
I believe the answer is:
rests
I believe this is a double definition.
'supports' is the first definition.
(rest is a kind of support)
'one isn't working' is the second definition.
(I've seen this in another clue)
'when' acts as a link.
(Other definitions for rests that I've seen before include "Reposes" , "Takes one's ease" , "Relaxes, sleeps" , "holidays" , "Takes a break" .)