Desert, leave behind (7)
I believe the answer is:
abandon
This clue is a double definition.
'desert' is the first definition.
(synonyms)
'leave behind' is the second definition.
(abandoning is a kind of leaving behind)
(Other definitions for abandon that I've seen before include "Cast aside" , "Lack of inhibition; desert" , "Total lack of inhibition (often gay?)" , "Forsake, leave behind" , "a complete lack of restraint" .)