The phrase "be wavy" is a term that is used to describe the appearance of hair or water that has a series of curves or undulations. There are several synonyms for the phrase "be wavy," including the words ripple, undulate, curl, twist, flow, and sway. These words help to convey different aspects of the wavy appearance, such as the smoothness of the curves, the curling, and twisting of the waves, or the flowing and swaying motion of the water. By using these synonyms, we can add depth and nuance to our descriptions of wavy textures and movements.