I don’t know if I can argue that it’s a word high-schoolers ought to know, but if you think so, then here is a context clues worksheet on the noun misnomer. It means “a use of a wrong or inappropriate name” and “a wrong name or inappropriate designation.”
Misnomer does appear fairly often in educated discourse.
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.