stubbornly refusing to change opinions, decisions, etc or courses of action
not inclined to feel sympathy or be swayed by feelings of sympathy; hardhearted
If you remain callous and obdurate, I shall perish as he did, and you will know why — W S Gilbert
obduracy /-si/ noun
obdurately adv
obdurateness noun
[Middle English from Latin obduratus, past part. of obdurare to harden, from ob- + durare to harden, from durus hard]