Disapproval is what you express when you share your dislike or opposition. If you fail a class, you might worry both about your grade point average and also your parents' disapproval.
When you sense disapproval in your teacher's voice after you show her a draft of your research paper, you might want to start over. You might feel disapproval yourself when you see your friend spend money instead of saving it, or watch your dad feel the dog from his plate at the dinner table. Disapproval uses the "opposite of" prefix dis- with approval, from its Latin root approbare, "to regard as good."