Definition of motorhead in English:

motorhead

Pronunciation /ˈməʊtəhɛd/

noun

slang US
  • 1A motor car or motorcycle enthusiast.

  • 2An idiot, a fool.

    Recorded in U.S. oral use in 1973 in J. E. Lighter's Hist. Dict. Amer. Slang: ‘A motorhead is a real idiot. A guy [I know] up in Maine says it all the time.’.

Origin

1970s; earliest use found in Campus Slang. From motor + head.