The rest of the night (5)
I believe the answer is:
sleep
'the rest' is the definition.
('sleep' can be a synonym of 'rest')
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for sleep that I've seen before include "Doze, nap" , "crash" , "Natural state of unconscious rest" , "Drop off" , "Snooze" .)