Car beginning to turn into desolate area (5)
I believe the answer is:
motor
'car' is the definition.
(thesaurus)
'beginning to turn into desolate area' is the wordplay.
'beginning to' says to take the initial letters.
'into' means one lot of letters goes inside another.
'desolate area' becomes 'moor' (I've seen this before).
The initial letter of 'turn' is 't'.
't' placed into 'moor' is 'MOTOR'.
(Other definitions for motor that I've seen before include "Drive" , "Make good progress" , "Car; travel quickly" , "Travel by car, engine" , "Machine that converts energy into motion" .)