This seat is uncomfortable for a nap (6)
I believe the answer is:
siesta
This clue might be a double definition.
'this seat is uncomfortable' is the first definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'for a nap' is the second definition.
(siesta is a kind of nap)
Can you help me to learn more?
(Other definitions for siesta that I've seen before include "Afternoon sleep" , "Forty winks" , "Diurnal nap in Spain" , "PM snooze" , "After lunch nap" .)