Do you know ghouls from goblins and ghosts?
Old English grunnettan "to grunt," frequentative of grunian "to grunt," probably imitative (cf. Danish grynte, Old High German grunnizon, German grunzen "to grunt," Latin grunnire "to grunt"). Related: Grunted; grunting.
1550s, from grunt (v.); as a type of fish, from 1713; meaning "infantry soldier" emerged in U.S. military slang during Vietnam War (first recorded in print 1969); used since 1900 of various low-level workers. Grunt work first recorded 1977.
any of about 75 species of marine fishes of the families Pomadasyidae and Banjosidae (order Perciformes). Grunts are found along shores in warm and tropical waters of the major oceans. They are snapperlike but with weaker teeth and are named for the piglike grunts they can produce with their pharyngeal (throat) teeth. Some (genus Haemulon) are further characterized by bright, reddish mouth linings. Grunts are edible and valued as food, though most species are small. Some are noted for a behavioral trait in which two individuals approach and "kiss." The purpose of this, whether sexual or aggressive, is not known.