1.A deep, guttural sound, as of a hog.
2.(Zool.) Any one of several species of American food fishes, of the genus Haemulon, allied to the snappers, as, the black grunt (Haemulon Plumieri), and the redmouth grunt (Haemulon aurolineatus), of the Southern United States; also applied to allied species of the genera Pomadasys, Orthopristis, and Pristopoma. Called also pigfish, squirrel fish, and grunter; so called from the noise it makes when taken.
3.A U. S. infantryman; used especially of those fighting in the war in Vietnam. (slang)
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