Have you ever made the mistake of saving a misspelled word during spell check instead of correcting it? If so, you are definitely not alone. Here is a quick screencast to show you how to unlearn the word that you've taught your computer.
I had a teacher ask me if there was a way to hide or remove students who are no longer in your class. The answer is maybe. It depends on if they are officially dropped from your class and appearing as red in your roster and gradebook. If not, then no, you cannot remove them until they have been unenrolled from the class. If the student is showing up as red in your gradebook though, you can hide them so you don't have to worry about them. Here is a screenshot to help you do it: