IPA: /ˈɒb.stɪ.nət.nəs/
KK: /ˈɑbstəˌneɪnəs/
The quality of being stubborn and refusing to change one's mind or actions, even when it may be unreasonable to do so.
His obstinateness made it difficult for him to accept help from others.
Obstinateness → It is formed from "obstinatus" (from Latin, meaning stubborn or persistent) and the suffix "-ness" (meaning the state or quality of). The word "obstinateness" refers to the quality of being stubborn or unyielding in attitude or behavior.
Think of someone who is 'stubborn' ('obstinatus') and remember that 'obstinateness' means the quality of being stubborn.