Rise and fall is a phrase used to describe the cyclical nature of many things, such as the stock market, the economy, and even emotions. FLUCTUATE (9 letters) is a verb meaning to change or vary irregularly, often between two extremes. TIDE (4 letters) is a noun referring to the alternate rising and falling of the sea. HEAVE (5 letters) is a verb meaning to lift or move something with great effort. UNDULATE (8 letters) is a verb meaning to move in a wavelike pattern. BOB (3 letters) is a verb meaning to move up and down with short, quick movements. Together, these words all describe the concept of rise and fall, which is the idea that things can go through cycles of increase and decrease.