Green’s Dictionary of Slang

1. an alcoholic, a heavy drinker.

1931		O. Von Gulker ‘Boomtown Album’ in Botkin Folk-Say 223: Where the hell’s that jarhead that said I couldn’t come to his dance?
1948		Z.N. Hurston Seraph on the Suwanee (1995) 909: We will all shuck shrimp for cooking, and rush that no-count jar-head back to heading shrimp.
1985		N. Pileggi Wiseguy (2001) 38: He insisted on calling them ‘jar heads’ and ‘jar ears’.
2011		F. Bill ‘Trespassing betwen Heaven and Hell’ in Crimes in Southern Indiana [ebook] He called Everett a stupid-ass, dink-lovin’ jarhead.

2. (US) a US Marine.

1943		Hubbard Gungo Ho [film script] You silly jarhead. When are you gonna learn to fix a pack [HDAS].
1960		(con. 1950) R. Leckie March to Glory (1962) 20: That single breed of American Marine — the ‘Jarheads,’ as the swab-jockies called them.
1971		T. Whitmore Memphis-Nam-Sweden 104: Jarhead, that sounds like Injun talk to me.
1981		J. Wambaugh Glitter Dome (1982) 74: If they had jarheads like you back in the big war, they’d a had to take that flag and suck it or fuck it to get it up on Iwo Jima.
1993		T. Jones Pugilist at Rest 9: None of my fellow-jarheads reported me.
2005		C. Buzzell My War (2006) 11: The idea of being a jarhead didn’t seem quite so appealing.
2008		Simon & Burns ‘Cradle of Civilization’ Generation Kill ep. 2 [TV script] Psycho-assed jarheads.
2017		S.M. Jones August Snow [ebook] ‘First job was getting jarheads the equipment they needed to do their job’.

3. attrib. use of sense 2.

1931		Reno (NV) Eve. Gazette 17 Sept. 12/1: However, the stars of the Army eleven have already begun to show their wares. The big gun of the Jarhead attack is Nodgie Ganuzzi, for the last five years premier halfback on West Coast Army elevens.
1990		(con. c.1970) G. Hasford Phantom Blooper 21: We need us a jarhead song. The Green Beanies have got their own song, and they ain’t shit. What we need is a Marine song. A song for grunts.
1991		B. Hamper Rivethead (1992) 11: The education-through-intimidation technique [...] was not unlike the jarhead gang mentality of the General Motors floorlords.
2002		J. Lerner You Got Nothing Coming 93: A lean, leathery whip of a man with a jarhead crew cut and a face like a clenched fist.
2017		S.M. Jones August Snow [ebook] ‘Is it true you had a kill four hundred yards out with a five-kilometer-an-hour crosswind, Lance Corporal? [...] Or is that just more jarhead bullshit?’.