rigidity [rigidities](The quality or state of being rigid) noun [UK: rɪ.ˈdʒɪ.dɪ.ti] [US: rɪ.ˈdʒɪ.də.ti]
stiffness [stiffnesses](rigidity) noun [UK: ˈstɪf.nəs] [US: ˈstɪf.nəs]She stretched to relieve the stiffness in her back. = Ella se estiró para aliviar su rigidez de espalda.