Inflexible (adjective)

1. Unable to bend or be forced out of shape; not flexible.
2. Stiff and unyielding; unwilling or unable to change.
3. Strict and unyielding in one's opinions, attitudes, or beliefs.

Origin:

Early 17th century: from french inflexible or late latin inflexibilis, from in- "not" + flexibilis "flexible".

Examples:

1. The metal was inflexible and wouldn't bend.
2. She had an inflexible personality and wouldn't change her mind.
3. He was inflexible in his political views.
4. An inflexible schedule made it difficult to make changes.
5. The company's inflexible policies caused frustration among employees.