The rest of the afternoon? (6)
I believe the answer is:
siesta
'the rest of the afternoon' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for siesta that I've seen before include "Daytime nap" , "Spanish afternoon activity" , "Early afternoon nap" , "Rest in the heat of the day" , "Afternoon nap in Cadiz" .)