The antonyms for the phrase "most hard-wearing" can be fragile, delicate, flimsy, weak, and brittle. These words indicate the opposite of durability, toughness, and resilience. A fragile material can easily break or be damaged, and a delicate one requires careful handling. Flimsy and weak suggest a lack of strength and stability. Brittle materials, on the other hand, may appear hard, but they are often prone to cracking or shattering. When choosing products or materials for long-term use, it is important to consider their durability and strength, avoiding those that are fragile, delicate, flimsy, weak, or brittle.