The term 'yahoo' was coined by the Anglo-Irish satirist Jonathan Swift in his 1726 novel Gulliver's Travels. He used it as the name for a race of filthy, savage, and degenerate humanoid creatures, contrasting them with the rational horses, the Houyhnhnms. The name was likely invented for its harsh, exclamatory sound to evoke a sense of crude barbarity. In the 20th century, the word entered general English as a lowercase term for a boorish, loutish, or unsophisticated person, directly extending Swift's satirical creation into a common label for uncivilized behavior.

The word is a simplex. It was invented by Jonathan Swift in the 18th century, likely as a nonsense word meant to sound brutish and uncouth.