unbendable
/ʌnˈbɛndəbəl/Definitions
1. adjective
Impossible to bend or be bent; rigid or unyielding.
“The unbendable branch of the tree made it difficult to pass through the thicket.”
2. noun
A person or thing that is unbendable, especially in their refusal to change their opinion or behavior.
“He was known as an unbendable negotiator, refusing to compromise on any point.”