according to dreammoods.com...
To dream that you are standing at the edge of a cliff, indicates that you have reached an increased level of understanding, new awareness, and a fresh point of view. You have reached a critical point in your life and are afraid of losing control. Alternatively, it suggests that you are pondering a life-altering decision.
To dream that you or someone falls off a cliff, suggests that you are going through some difficult times and are afraid of what is ahead for you. You fear that you may not be up for the challenge or that you cannot meet the expectations of others.
To dream that you are climbing to the top of a cliff, symbolizes your ambition and drive. The dream may parallel your desires to achieve success and be the at the top of your profession. It is analogous to climbing the corporate ladder.