Someone incredibly, obnoxiously stupid. The word is a conflation of MONGoloid and buffOON.
Rush Limbaugh and other raving commentators of that ilk are major MONGOON's.
by Chazz9 June 16, 2011
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1. Fun to hang out with
2. Another word for cool, chill, tight, fantastic, awesome.
He's mongoon to chill with

Instead of saying he's chill to chill with, because that sounds too redundant
by Cassi and Mollie September 2, 2007
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