The word "ethnarch" generally refers to a leader of a particular ethnic group. However, there are several other synonyms that can be used in place of this word. One of these synonyms is "tribal chief," which refers to a leader of a specific tribe or community. Another synonym is "clan chieftain," which refers to a leader of a clan or family. "Nationalist leader" is another possible synonym, particularly if the individual is involved in political movements or activism related to their ethnic group. Ultimately, the choice of synonym will depend on the specific context in which the word is being used and the particular connotations that the speaker or writer wishes to convey.