Relaxed in boiling desert (6)
I believe the answer is:
rested
'relaxed' is the definition.
(I've seen this before)
'boiling desert' is the wordplay.
'boiling' is an anagram indicator.
'desert' is an anagram of 'RESTED'.
'in' is the link.
(Other definitions for rested that I've seen before include "Took a break from activities" , "Relaxed, took a break" , "Took one's ease" , "Reposed or took a breather" , "Took break in desert" .)