The phrase "most nothing" is itself an undefined term that doesn't lend itself easily to antonyms. However, a careful consideration of its meaning could yield several potential opposites. One possibility could be "entirety," meaning everything or the whole amount of something. Another could be "abundance," meaning an excessive or overflowing quantity. Yet another option could be "plenitude," suggesting a fullness or completeness. Alternatively, one could consider antonyms for the word "nothing" on its own, such as "everything," "something," or "anything." Ultimately, the choice of antonyms depends on the intended meaning and context of the original phrase.