The antonyms for the word "most softshell" are hard, firm, rigid, solid, tough, unyielding, inflexible, and harsh. These terms describe materials or objects that are sturdy, strong, and durable, which contrasts with the soft and pliable nature of a softshell. A hard shell, for example, is a shell that is made of tough and durable material that can withstand harsh conditions and protect the contents inside. By comparison, a softshell fabric might be comfortable to wear and offer some protection from the elements, but it is not as sturdy or long-lasting as a hard shell. Understanding these antonyms helps to provide a better understanding of the characteristics of different materials and products.