There are a variety of synonyms for the phrase "make calm" that can help convey a sense of peace and tranquility. Some synonyms include "soothe," "settle," "compose," "pacify," "calm down," "relax," "assuage," "appease," "quiet," "lull," "mollify," "placate," and "tranquilize." All of these terms suggest a sense of quieting the mind and easing tensions. Depending on the context, different synonyms may be more appropriate than others. For example, "soothe" might be used to describe the way a gentle massage can help relax someone, while "pacify" might be used to describe diffusing a heated argument.