Peels back to reveal the rest (5)
I believe the answer is:
sleep
'the rest' is the definition.
(synonyms)
'peels back' is the wordplay.
'back' says the letters should be written in reverse.
'peels' written backwards gives 'SLEEP'.
'to reveal' acts as a link.
(Other definitions for sleep that I've seen before include "Snooze" , "Shut-eye" , "Wayne _; former Royal Ballet principal dancer" , "Produced (egg)" , "Natural state of unconscious rest" .)