The term "most unsustained" refers to something that lacks support or validation. Its antonyms include "supported," "substantiated," "validated," "substantive," "proven," "verified," "confirmed," "corroborated," "legitimate," "established," "valid," "founded," "credible," "justified," "backed," "reinforced," and "endorsed." These words suggest a sense of trustworthiness or reliability for a particular thing or idea. In contrast, "most unsustained" implies doubt or uncertainty, making it crucial to seek out antonyms that can provide clarity and confidence for any given situation.