Midday nap (6)
I believe the answer is:
siesta
'midday nap' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for siesta that I've seen before include "Early afternoon nap" , "PM snooze" , "Spanish afternoon nap" , "Rest in the heat of the day" , "Daytime nap" .)