Abstract: A speed-adaptive dynamic-vibration absorber for a shaft rotatable about an axis, including a hub part on which at least one inertial mass is provided. The at least one inertial mass, starting from a middle position in which its center of gravity is the greatest distance from the axis, is moveable back and forth relative to the hub part along a path of motion in deflection positions in which the distance of the center of gravity of the at least one inertial mass changes with respect to the middle position, the path of motion having a radius of curvature which changes at least section-by-section with increasing deflection of the inertial mass out of the middle position.