Be out for the rest of the night (5)

I believe the answer is:

sleep

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'rest of the night' is the definition.
'sleep' can be an answer for 'rest' (synonyms). I am unsure of the 'of the night' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for sleep that I've seen before include "Slumber" , "Snooze" , "Natural state of unconscious rest" , "Shut-eye" , "Produced (egg)" .)

I've seen this clue in the Evening Standard.

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