From Gulliver's Travels by Jonathan Swift, where Yahoo is the name of a race of brutes.
Meanings
(derogatory) A rough, coarse, loud or uncouth individual.
Triple Threat Triad? I beat up some of those yahoos when I got into town. 2012 April 21, Michael Dante DiMartino, Bryan Konietzko, “The Revelation” (7:01 from the start), in Joaquim Dos Santos, Ki Hyun Ryu, directors, The Legend of Korra, season 1, episode 3, spoken by Korra (Janet Varney):
A humanoid cryptid said to exist in parts of eastern Australia, and also reported in the Bahamas.
1835, James Holman, Travels, quoted by Malcolm Smith, Bunyips and Bigfoots (Millennium Books, 1996, →ISBN), who notes that the Australian sense almost certainly derives from Gulliver's Travels, despite Holman's report
The natives are greatly terrrified by the sight of a person in a mask calling him "devil" or Yah-hoo, which signifies evil spirit.
Ah! You mean you have been 'yahooing'? I'm dead! 2007, Tell:
In other words, none of our googling and yahooing is private (you knew that, right ?). 2017, Rajendra Pillai, Unearthed: Discover Life as God's Masterpiece, New Hope Publishers, →ISBN: