Which characteristic describes a workpiece or machine setup that is stiff and inflexible?

The term that accurately describes a workpiece or machine setup that is stiff and inflexible is rigidity. Rigidity refers to the resistance of an object to deformation under external forces. In metal cutting processes, having a rigid setup is crucial as it helps maintain stability and precision during machining. A rigid workpiece or machine supports the cutting tool effectively, reducing vibrations and maintaining the desired dimensions and surface finish of the part being machined.

Meanwhile, flexibility and elasticity pertain to the ability of a material to deform and return to its original shape, characteristics that are typically not desirable in a machining context because they can lead to inaccuracies. Softness refers to the ease with which a material can be shaped or deformed, and again, this does not align with the concept of stiffness or inflexibility required for effective cutting operations.