an old term for a retard or someone with mongolism. some, who must be mongolian idiots themselves, like to confuse this term with mongoloid idiot which is not a real term. mongolian idiot is a term within itself. a mongoloid idiot is merely an idiot who is mongolian. DO NOT get them confused unless you want to be a total douche.
that kid is eating his helmet when he should be wearing it. oh he must be a mongolain idiot.