A gang working in desert (7)
I believe the answer is:
abandon
'desert' is the definition.
(synonyms)
'a gang working' is the wordplay.
'gang' becomes 'band' (both can mean a group of people).
'working' becomes 'on' (on can mean working or activated).
'a'+'band'+'on'='ABANDON'
'in' acts as a link.
(Other definitions for abandon that I've seen before include "Lack of inhibition; desert" , "ditch" , "Forsake, leave behind" , "Walk out on" , "Desert or yield without restraint" .)