Arab beginning to service car (5)
I believe the answer is:
saudi
'arab' is the definition.
(someone from Saudi Arabia)
'beginning to service car' is the wordplay.
'beginning to' says to take the initial letters.
'car' becomes 'audi' (Audi is a German car brand).
The first letter of 'service' is 's'.
's'+'audi'='SAUDI'
(Other definitions for saudi that I've seen before include "Native of kingdom" , "Native of Riyadh, possibly" , "one accustomed to hot, dry conditions?" , "Middle-Easterner" , "One from Riyadh" .)