German motor car pioneer (4)
I believe the answer is:
benz
(Other definitions for benz that I've seen before include "German pioneer of the internal-combustion engine, associated with Mercedes" , "Motor man" , "German engineer who built the first petrol-engined car" , "German engineer, builder of first car with internal combustion engine" , "German engineer, first to build a patented car, d. 1929" .)