The term "most riven" implies division or disagreement, hence its antonyms are words that denote cohesion, unity, or agreement. Some of the antonyms for "most riven" include united, undivided, harmonious, cohesive, and agreeing. "United" means forming a single unit or entity, while "undivided" refers to being free from division or conflict. "Harmonious" means peacefully coexisting, and "cohesive" denotes having different parts working together as a whole. "Agreeing" means being in complete harmony or unity with others. Therefore, these antonyms represent the exact opposite of "most riven," and their use in various contexts can help to emphasize a sense of agreement, harmony, or unity.