The word "conclusivenesses" refers to the quality of being conclusive or decisive. Its antonyms, on the other hand, would be related to indecisiveness or uncertainty. Some possible antonyms for "conclusivenesses" could include ambiguity, vagueness, doubt, hesitancy, or equivocation. These words suggest a lack of clarity or resolution, and they can be used to describe situations, arguments, or decisions that are still in flux or open to interpretation. While conclusiveness is often seen as desirable in fields like law, science, or philosophy, there are certainly instances where a more nuanced or uncertain approach is more appropriate.