Antonyms for the word "most self-sustaining" include "dependent," "needy," and "vulnerable." These words indicate a lack of autonomy and the need for constant support and assistance. Whereas self-sustaining implies independence and resilience, these opposites suggest fragility and reliance on others. Other antonyms might include "unstable," "unreliable," or "unpredictable," all indicating a lack of consistency, discipline, or durability. By considering these opposites, we can see the value of being self-sustaining and recognize the risks of relying too heavily on others. Being self-sustaining requires effort, planning, and determination, but the rewards of independence and security are worth it.