What does "inflexibility" mean?

Inflexibility: The quality or state of being inflexible, or not capable of being bent or changed; unyielding stiffness; inflexibleness; rigidity; firmness of will or purpose; unbending pertinacity; steadfastness; resoluteness; unchangeableness; obstinacy. The inflexibility of mechanism. A. Baxter. That grave inflexibility of soul. Churchill. The purity and inflexibility of their faith. T. Warton.