O / obdūrātĭo
noun

obdūrātĭo

gen. obdūrātōnis · gender feminine · decl. 3rd
a hardening;; obduration, obduracy
a hardening; of the mind, obduration, obduracy (eccl. Lat.), Aug. Ep. 105; id. in Psa. 77 et saep.