Untoughened refers to something that is not hardened, strengthened or toughened. Its antonyms, therefore, are words that describe the opposite of such a state. Some of the antonyms for untoughened are hardened, toughened, strengthened, braced, fortified, tempered, seasoned and matured. These words suggest a level of resilience, durability and strength that comes with the passage of time and experience, as well as the ability to withstand stress, pressure or adversity. Therefore, when we describe something as untoughened or weak, its antonyms help us to express the idea of strength, resilience and fortitude.