To dream that you are standing at the edge of a cliff implies that you are at an important crossroads in your life. You have a difficult decision to make, and you are fearful of choosing the wrong option. Perhaps you finally comprehend some previously misunderstood issue, or you have developed a different opinion.
To dream that you or someone falls off a cliff represents your fears and hesitations about an issue or situation that you need to tackle in the future. You doubt your ability to overcome these obstacles.