The antonyms for the phrase "most persisting" depends on the context of the sentence. If the sentence is referring to a person's behavior, then antonyms could include "inconsistent," "fickle," or "capricious." In contrast, if the sentence is referring to an object's durability or longevity, antonyms could include "fragile," "delicate," or "perishable." Additionally, in terms of emotions or mental states, antonyms for "most persisting" could include "fleeting," "ephemeral," or "transitory." Overall, the antonyms for "most persisting" vary depending on the context and the subject being described.