Inflexible

Part of speech: adjective (a.)

1. Not capable of being bent; stiff; rigid; firm; unyielding.

2. Firm in will or purpose; not to be turned, changed, or altered; resolute; determined; unyieding; inexorable; stubborn. "Inflexibleas steel." Miltom. Amanof upright and inflexibletemper . . . can overcome all private fear. Addison.

3. Incapable of change; unalterable; immutable. The nature of things is inflexible. I. Watts.

Synonyms: -- Unbending; unyielding; rigid; inexorable; pertinacious; obstinate; stubborn; unrelenting.