Definition of jarhead in English:

jarhead

noun

US informal
  • A marine.

    ‘A lot is made in many movies of the physical training and the technical training that they experience in boot camp but I really think boot camp is to turn you into a jarhead.’
    ‘I know what I meant, jarhead, I don't need the likes of you questioning my command of the language.’

Origin

Early 20th century (originally US dialect, in the sense ‘mule’): from jar+ head. The word originally referred to members of the US army, on account of the mule mascot of the Army football teams.

Pronunciation

jarhead