Definition of jarhead in English:

jarhead

noun

US
informal
  • A US Marine.

    • ‘After all, how could some jarhead Marine know more about any subject than the Washington Post?’
    • ‘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.’
    • ‘The entire manner in which the heavily criticized Patriot Act was passed into law is enough to give even the most jingoistic jarhead reason to pause.’

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

/ˈjärˌhed/