Which term best describes a lack of sharpness?

The term that best describes a lack of sharpness is "blunt." In various contexts, such as in reference to tools, knives, or even certain types of discussion, "blunt" indicates an absence of a sharp edge or point, which means something cannot easily cut or penetrate. When something is blunt, it is characterized by a rounded or less acute edge, thus lacking the precision or sharpness needed for specific tasks.

Although the other terms mention aspects of texture or shape, they do not specifically imply a lack of sharpness. "Soft" refers to the lack of hardness, "pointed" indicates a sharp and acute end, and "smooth" describes a surface texture without bumps or roughness, none of which directly correlate with sharpness. Thus, "blunt" is the term that most clearly conveys the idea of lacking sharpness.