The French term "maitre de" translates to "master of" in English, and there are several synonyms that can be used depending on the context. If referring to a person who is an expert in their field, words like "specialist," "authority," or "guru" may be appropriate. For someone who is in charge or responsible for a group, "leader," "boss," or "head" could be used. In the context of entertainment, "emcee," "host," or "compere" might be interchangeable with "maitre de." When describing a person who is simply skilled or accomplished, "champion," "ace," or "virtuoso" could also be synonyms.