a type of slur, or insult mostly used by American stereotypes. It can also be a relative of the phrases like, "ur gay", "ur mom", and plenty of more.
It can also be used by a person with terrible roasting, and just saying "your fat" when you weigh only
102 pounds.
Elementary &
Middle school kids, (and sometimes
highschoolers) say it for cool, trying not to get a rejection from the "cool kids".