IPA: /ɪnˈflɛksəblnəs/
KK: /ɪnˈflɛksəblnəs/
The quality of being unable to change or adapt; a stubbornness that does not allow for flexibility or compromise.
His inflexibleness made it difficult for him to work with others on the project.
Inflexibleness → It is formed from "in-" (meaning not), "flexibilis" (from Latin, meaning bendable or pliable), and "-ness" (meaning the state of being). The word describes the state of being not bendable or rigid.
Think of 'not' ('in-') being 'bendable' ('flexibilis') — that's why inflexibleness means the state of being rigid.