Inflexible
Part of speech: adjective
Definition: Not flexible; not capable of bending or being bent; stiff; rigid; firm; unyielding. Not willing to change, e.g. one's opinion or habits; obstinate; stubborn; resolute; determined.
Example sentence: It seems to be a law of nature, inflexible and inexorable, that those who will not risk cannot win.
Unbending
Part of speech: adjective
Definition: inflexible and not yieldingvery reserved, aloof and antisocial
Part of speech: verb
Definition: To remove a bend so as to make, or allow to become, straight