"De terminative" refers to something that is definite and clear-cut. Antonyms for this word could include: indefinite, vague, uncertain, ambiguous, unclear, imprecise, and ambiguous. These words denote a lack of clarity or precision, and suggest that something is open to interpretation or subject to change. While "de terminative" implies a sense of finality, these antonyms signify a lack of resolution or certainty. Depending on the context of usage, each of these words could provide a useful counterpoint to "de terminative," whether in discussing concepts, ideas, or outcomes.