To utter a deep guttural sound, as a hog does. To utter a sound similar to a grunt, as in disgust. To utter or express with a deep guttural sound: He merely grunted his approval. A deep guttural sound. Any of various chiefly tropical marine fishes of the family Haemulidae that, upon removal from the water, produce grunting sounds by rubbing together tooth plates in the throat. Slang An infantryman in the U.S. military, especially in the Vietnam War: "They were called grunts....They were the infantrymen, the foot soldiers of the war\u201d ( Bernard Edelman). Slang One who performs routine or mundane tasks. New England A dessert made by stewing fruit topped with pieces of biscuit dough, which steam as the fruit cooks. Also called slump.