A term used to describe a US Marine. Although some believe the term is of recent origin (Gulf
War), it has been around for a long time (at least since World
War II). It has nothing to do with haircuts, hats or headshape. It refers to the Marines propensity to follow orders, regardless of consequences or personal safety. Because of their
single-minded willingness to put their duty before themselves, Marines are said to have jarheads...hard on the outside and empty on the inside. It is a good thing there are such
men.