Relaxed in desert conditions (6)
I believe the answer is:
rested
'relaxed' is the definition.
(I've seen this in another clue)
'desert conditions' is the wordplay.
'conditions' indicates an anagram (condition can mean to influence or treat).
'desert' is an anagram of 'RESTED'.
'in' acts as a link.
(Other definitions for rested that I've seen before include "Reposed or took a breather" , "Took a break from activities" , "Took one's ease" , "Relaxed, took a break" , "Took break in desert" .)