1.  yahoo(n = noun.person) bumpkin, chawbacon, hayseed, hick, rube, yokel - a person who is not very intelligent or interested in culture;
is a kind of rustic

2.  yahoo(n = noun.person) - one of a race of brutes resembling men but subject to the Houyhnhnms in a novel by Jonathan Swift;
is a kind of character, fictional character, fictitious character

3.  yahoo(n = noun.communication) - a widely used search engine for the web that finds information, news, images, products, finance;
is a kind of search engine

1.  One of a race of filthy brutes in Swift's “Gulliver's Travels.” See in the Dictionary of Noted Names in Fiction. [Webster 1913 Suppl.]

2.  Hence, any brutish or vicious character. [Webster 1913 Suppl.]

3.  A raw countryman; a lout; a greenhorn. [Webster 1913 Suppl.]

yahoo, n. a coarse bestial person.

Etymology:
name of an imaginary race of brutish creatures in Swift's Gulliver's Travels (1726)

N  commonality, commonalty, democracy, obscurity, low condition, low life, low society, low company, bourgeoisie, mass of the people, mass of society, Brown Jones and Robinson, lower classes, humbler classes, humbler orders, vulgar herd, common herd, rank and file, hoc genus omne, the many, the general, the crowd, the people, the populace, the multitude, the million, the masses, the mobility, the peasantry, king Mob, proletariat, fruges consumere nati, demos, hoi polloi, great unwashed, man in the street, mob, rabble, rabble rout, chaff, rout, horde, canaille, scum of the people, residuum of the people, dregs of the people, dregs of society, swinish multitude, foex populi, trash, profanum vulgus, ignobile vulgus, vermin, riffraff, ragtag and bobtail, small fry, commoner, one of the people, democrat, plebeian, republican, proletary, proletaire, roturier, Mr, Snooks, bourgeois, epicier, Philistine, cockney, grisette, demimonde, peasant, countryman, boor, carle, churl, villain, villein, terrae filius, son of the land, serf, kern, tyke, tike, chuff, ryot, fellah, longshoreman, swain, clown, hind, clod, clodhopper, hobnail, yokel, bog-trotter, bumpkin, plowman, plowboy, rustic, hayseed, lunkhead, chaw-bacon, tiller of the soil, hewers of wood and drawers of water, groundling, gaffer, loon, put, cub, Tony Lumpkin, looby, rube, lout, underling, gamin, rough, pot- wallopper, slubberdegullion, vulgar fellow, low fellow, cad, curmudgeon, upstart, parvenu, skipjack, nobody, nobody one knows, hesterni quirites, pessoribus orti, bourgeois gentilhomme, novus homo, snob, gent, mushroom, no one knows who, adventurer, man of straw, beggar, gaberlunzie, muckworm, mudlark, sans culotte, raff, tatterdemalion, caitiff, ragamuffin, Pariah, outcast of society, tramp, vagabond, bezonian, panhandler, sundowner, chiffonnier, Cinderella, cinderwench, scrub, jade, gossoon, Goth, Vandal, Hottentot, Zulu, savage, barbarian, Yahoo, unlicked cub, rough diamond, barbarousness, barbarism, boeotia, ignoble, common, mean, low, base, vile, sorry, scrubby, beggarly, below par, no great shakes, homely, homespun, vulgar, low-minded, snobbish, plebeian, proletarian, of low parentage, of low origin, of low extraction, of mean parentage, of mean origin, of mean extraction, lowborn, baseborn, earthborn, mushroom, dunghill, risen from the ranks, unknown to fame, obscure, untitled, rustic, uncivilized, loutish, boorish, clownish, churlish, brutish, raffish, rude, unlicked, barbarous, barbarian, barbaric, barbaresque, cockney, born within sound of Bow bells, underling, menial, subaltern, below the salt, dummodo sit dives barbarus ipse placet.