The word "most millenary" represents something that has been present or existed for thousands of years. There are several synonyms for this term that can be used depending on the context. One such synonym is "age-old," which refers to something that has been around for a very long time. Another word that can be used in place of "most millenary" is "ancient." This term refers to something that is old and has historical significance. Additionally, the word "time-honored" is another synonym that can be used in place of "most millenary." This word has the connotation of something that has been passed down from generation to generation and has stood the test of time.