The ability of the fastener material to resist internal sliding is its:

The correct answer is shear strength, as it specifically refers to the ability of a material to resist sliding forces that act parallel to the surface. When a shear load is applied to a fastener, it creates internal forces that can cause the material to deform or fail by sliding along a plane. Shear strength is particularly significant in fastener applications, as it determines how well a fastener can hold components together under various loads without experiencing shear failure.

In contrast, tensile strength measures a material's ability to resist being pulled apart, while compression strength refers to its ability to resist being squashed or compressed. Yield strength is the point at which a material begins to deform permanently. Though these other strengths are important for different aspects of a fastener's performance, they do not specifically address the internal sliding resistance that is characterized by shear strength.