implacability

• In its place was hard implacability, and she felt a moment's instinctive unease. —  Helen Bianchin - The Wedding Ultimatum
• For al Qaeda, its own fantasies and unbridled hubris coupled with its self-proclaimed, divinely ordained mission strengthen internal morale, resilience, and implacability in the face of overwhelming odds. —  News4Jax.com - Local News
• Thus much I write to let you know, I am more honest to my friends than happy in their cases amp;c As the fear of giving offence to the king of Scots was one reason or pretext for the implacability of the queen towards Davison, Essex hazarded the step of writing to request, as a personal favor to himself, the forgiveness and good offices of this monarch in behalf of the man who bore the blame of his mother's death. —  Memoirs of the Court of Queen Elizabeth
• Al-Moizz declared the verses excellent and showed more favour to the author than to any other literary man in the assembly Ready wit not less than poetical ingenuity could always win the respect of these gentlemen, whose cynical cold-bloodedness and implacability were ever ready to be diverted, provided that the diversion was intellectual. —  A Boswell of Baghdad With Diversions
• The hatred of the followers of Osiris to those of Typhon was perpetuated with such implacability, that the nomes which had persisted in adhering to the worship of Sit, became odious to the rest of the population: the image of their master on the monuments was mutilated, their names were effaced from the geographical lists, they were assailed with insulting epithets, and to pursue and slay their sacred animals was reckoned a pious act. —  History Of Egypt, Chaldæa, Syria, Babylonia, and Assyria, Volume 1 (of 12)

Roget's II: The New Thesaurus

Used in the Same Context