Seat is adjusted for rest (6)
I believe the answer is:
siesta
'for rest' is the definition.
(I've seen this before)
'seat is adjusted' is the wordplay.
'adjusted' indicates anagramming the letters.
'seat'+'is'='seatis'
'seatis' is an anagram of 'SIESTA'.
(Other definitions for siesta that I've seen before include "Afternoon rest" , "Diurnal nap in Spain" , "PM snooze" , "A Spanish mid-day nap" , "PM snoozing?" .)