This word is used in situations where someone has acted with complete ignorance and as result of this ignorance, he or she will have forfeited there dignity. It can also be used in situations where someone has performed with incompetence, most notably in the realm of sports.
After he or she has performed the act of ignorance or incompetence, his or her audience may respond with a chorus "HYULL's" OR telling the person that he or she is "HYULL".
person 1: "Where is France?"
person 2: "I think it's in America?"
person 3: "LOL, HYULL!"
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.