"Melt away" is an expression that describes the act of disappearing or gradually dissolving. There are a few synonyms that can be used interchangeably to convey the same meaning. One of them is "disappear slowly," which expresses the gradual process of something fading away. The phrase "dissolve into nothing" can also be used to describe the vanishing of something into thin air. Another option is "evaporate," which suggests the process of turning from liquid to gas and slowly disappearing. "Fade out" is another good synonym for "melt away," which implies something slowly disappearing over time until it is no longer present.