Unproper Posted in U Best definition Unproper Improper use of improper. Misinformed: Oh, yeah? It’s YOU’RE not your. Don’t use unproper grammar if you’re going to argue. Me: *facepalm* How satisfied are you with the definition? Looking for Unproper meaning? Delighted that you discovered the greatest determine on our web site! Recently this definition was actually observed 92 times.