Most whilom refers to the person or thing that existed or occurred a long time ago. Synonyms for most whilom include ancient, bygone, old-fashioned, outdated, outmoded, out-of-date, and passe. These words describe things or ideas that are no longer in trend or use. Another synonym for most whilom is archaic, which refers to something that is old-fashioned, but still has relevance in a particular field or discipline. Similarly, antediluvian can also be used as a synonym for most whilom, but it specifically refers to things or people that are extremely old or outdated. Using these synonyms can help add variety to your writing while conveying the same meaning as most whilom.