ob ‧ du ‧ rate /ˈɒbdjərət, ˈɒbdjʊrət $ ˈɑːbdə-/ BrE AmE adjective formal
[ Date: 1400-1500 ; Language: Latin ; Origin: past participle of obdurare 'to harden' ]
very determined not to change your beliefs, actions, or feelings, in a way that seems unreasonable SYN stubborn :
They argued, but he remained obdurate.
—obduracy noun [uncountable]
—obdurately adverb