The term "case-hardened" refers to something that has become tougher or more resistant to external forces. Antonyms for this term would include words like "soft," "weak," and "vulnerable." These words describe things that are easily damaged or broken, lacking in strength or durability. Other antonyms for "more case-hardened" might include words like "tender," "fragile," or "delicate," which suggest a lack of resilience or an inability to withstand pressure. Choosing the right antonym for "more case-hardened" depends on the context in which the word is being used, as well as the specific connotations and implications of each potential antonym.