rigidity

1. The quality or state of being rigid.
2. An instance of being rigid.

noun

1. The quality or state of being stubbornly inflexible: die-hardism, grimness, implacability, implacableness, incompliance, incompliancy, inexorability, inexorableness, inflexibility, inflexibleness, intransigence, intransigency, obduracy, obdurateness, relentlessness, remorselessness, rigidness, stubbornness. See resist/yield.
2. The fact or condition of being rigorous and unsparing: austerity, hardness, harshness, rigor, rigorousness, severity, sternness, strictness, stringency, toughness. See easy/hard.

The characteristic of being nonflexible, which is essential in a connector, a reciprocal arm, or an indirect retaining unit of a removable partial denture.

That property of a material which resists a change in its physical shape.

In the context of learning, an inability to change behaviour patterns, attitudes, or body postures.

Inflexibility or stiffness.

• clasp-knife r. — increased tension in the extensor of a joint when it is passively flexed, giving way suddenly on exertion of further pressure; seen especially in upper motor neuron disease.
• cogwheel r. — tension in a muscle that gives way in little jerks when the muscle is passively stretched.
• lead-pipe r. — posture adopted when the rigidity of the limb is maintained equally throughout the passive flexion.
• r. reflex — the state of immobility generated in female animals, especially those in estrus, when they make physical contact with a male.