From Spanish (mostly used in Spain), a derogatory word for someone with down-syndrome (Mongolism); English equivalent of mongo. It also can be used for retard, dumbass, spasty, jerk, junkhead etc. Mostly describes a person with very low IQ and behaving stupidly all day.
Que te pasa? Eres mongolico? What's wrong with you? Are you a mongo (mongolico)?