Italian automaker since 1899 (4)
I believe the answer is:
fiat
'italian automaker since 1899' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fiat that I've seen before include "Arbitrary order" , "Decree; Italian car make" , "Official sanction" , "Decree or official permission" , "Let it be done - it's a Latin order" .)