IPA: /ˈɒb.dʒʊə.nəs/
KK: /ˈɑb.dʒəˌreɪt.nəs/
The quality of being stubborn and refusing to change one's mind or actions.
His obdurateness in refusing to apologize caused many problems in the team.
Obdurateness → It is formed from "ob-" (meaning against) and "durare" (meaning to endure or last). The suffix "-ness" indicates a state or quality. Thus, the word "obdurateness" refers to the quality of being stubborn or resistant to change, enduring against persuasion or influence.
Think of being 'against' ('ob-') change and 'enduring' ('durare') stubbornly — that's what obdurateness means.