Madian is a relatively obscure word, and there aren't many commonly used synonyms for it. One possible alternative is "Midianite," which refers to a biblical group of people who were said to have lived in the Arabian Desert. Another less commonly used synonym is "Madyan," which is an alternate spelling of the same biblical group. Aside from these two options, there aren't many other words that would be interchangeable with "Madian." Some possible related terms might include "Nomadic," "Desert-dwelling," or "Arabian," which could be used to describe the Midianites and their way of life.