What was a grunt?

Answer 1

a grunt is the lowest class of the covenant. these dumb life forms act as canon fodder(making the canon look bigger than it actually is). grunts are approximately 4 foot tall. while being weak and helpless, a large pack of grunts can be incredibly deadly. grunts can often be scared off by killing their leaders(elites, brutes and higher rank grunts). some grunts are often sent out as suicidal grunts(more like kamikaze grunts) and can be seen charging at you carelessly with two armed plasma grenades, these can prove quite a threat. grunts can be seen wearing a triangular pack on their back. this is their methane supply and on halo reach, if removed, it can end up in making a grunt go superman(a grunt being thrown around in the air by his methane pack(jet packing) which will then blow up). grunts are the more comic species of the covenant and, although weak, precautions must be taken when dealing with large packs.

Answer 2

A Vietnam War US Infantryman (Vietnam War US Foot Soldier). US Marine grunts were sometimes called "grunts" but primarily US Marine riflemen.