You don't have to use a name at all. All you have to do is indicate what is needed if the student doesn't perform up to expectations. The idea that there needs to be a label is a fallacy.

And also the idea that a child who has below average intelligence (the ones labeled in this thread as "stoopid"), even though he/she has performed at his/her maximum ability, has failed, is also a fallacy.

Schools exist to help children learn things they need to know. They don't exist for the purpose of creating artificial designations of "winners" and "losers", and determining who fits into which category.