inflexible

Not easily bent; stiff or rigid. cross-reference: stiff.

Incapable of being changed; unalterable.

Refusing to change one's attitude, purpose, or principles; immovable.

Not flexible; incapable of bending or of being bent; rigid.

Unyielding in temper or purpose; that will not yield to prayers or arguments; firm in purpose; incapable of being turned; not to be prevailed on.