Equiponderant is not a term that is commonly used in everyday language. It means to be equal in weight or importance. Some synonyms for equiponderant could include balanced, equivalent, commensurate, on a par, even, corresponding, matched, and proportional. These terms all describe something that is balanced and equal in some way. It could be used to describe the weight of objects, the value or worth of something, or the importance of ideas or concepts. Though it may not be a commonly used term, its synonyms allow for clear communication when discussing the equal weight or importance of something.