Rest of the day? (3)
I believe the answer is:
nap
'rest of the day?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nap that I've seen before include "A short sleep or snooze" , "Card game - quick sleep" , "Kip" , "Short sleep on fuzzy fabric surface" , "Sleep - card game - fibres on a snooker table" .)