A Yahoo is a legendary being in the novel Gulliver's Travels (1726) by Jonathan Swift.
Description
In Gulliver's Travels the Yahoos are described by Swift as having a very peculiar shape. Their heads and breasts were covered with a thick hair, some frizzled and others lank, they had beards like goats and a long ridge of hair down their backs, and the foreparts of their legs and feet, but the rest of their bodies was bare, so that their skins, which were of a brown-buff colour, could be seen.
They had no tails, and they sat on the ground as well as laid down, and often stood on their hind feet. They climbed high trees as nimbly as a squirrel, for they had strong extended claws before and behind, terminating in sharp points and hooked. They would often spring and bound and leap with prodigious agility.
Behavior
Swift describes the Yahoos as vile and savage creatures, filthy and with unpleasant habits, resembling human beings far too closely for the liking of protagonist Lemuel Gulliver, who finds the calm and rational society of intelligent horses, the Houyhnhnms, far preferable.
The Yahoos are primitive creatures obsessed with "pretty stones" they find by digging in mud, thus representing the distasteful materialism and ignorant elitism Swift encountered in Britain. Hence the term "yahoo" has come to mean "a crude, brutish or obscenely coarse person".