Not to be placated or appeased or moved by entreaty:
— Russia's final hour, it seemed, approached with inexorable certainty.

synonyms: grim, relentless, stern, unappeasable, unforgiving, unrelenting.

Roget 601: necessary, needful etc. (requisite) 630.    fated; destined etc. v.; elect; spellbound compulsory etc. (compel) 744; uncontrollable, inevitable, unavoidable, irresistible, irrevocable, inexorable; avoidless^†, resistless.    involuntary, instinctive, automatic, blind, mechanical; unconscious, unwitting, unthinking; unintentional etc. (undesigned) 621; impulsive etc. 612.    ... show more

Roget 919: revengeful, vengeful; vindictive, rancorous; pitiless etc. 914.1; ruthless, rigorous, avenging.    unforgiving, unrelenting; inexorable, stony-hearted, implacable; relentless, remorseless.    aeternum servans sub pectore vulnus [Lat.]; rankling; immitigable.    ... show more

Roget 914a: pitiless, merciless, ruthless, bowelless; unpitying, unmerciful, inclement; grim-faced, grim-visaged; incompassionate^†, uncompassionate; inexorable; harsh etc. 739; unrelenting etc. 919.    ... show more

Roget 744: compelling etc. v.; coercive, coactive^†; inexorable etc. 739; compulsory, compulsatory^†; obligatory, stringent, peremptory.    forcible, not to be trifled with; irresistible etc. 601; compelled etc. v.; fain to.    ... show more

Roget 739: severe; strict, hard, harsh, dour, rigid, stiff, stern, rigorous, uncompromising, exacting, exigent, exigeant^†, inexorable, inflexible, obdurate, austere, hard-headed, hard-nosed, hard-shell [U.S.], relentless, Spartan, Draconian, stringent, strait-laced, searching, unsparing, iron-handed, peremptory, absolute, positive, arbitrary, imperative; coercive etc. 744; tyrannical, extortionate, grinding, withering, oppressive, inquisitorial; inclement etc. (ruthless) 914.1; cruel etc. (malevolent) 907; haughty, arrogant etc. 885; precisian^†.    ... show more

Roget 604: resolved etc. v.; determined; strong-willed, strong-minded; resolute etc. (brave) 861; self-possessed; decided, definitive, peremptory, tranchant^†; unhesitating, unflinching, unshrinking^†; firm, iron, gritty [U.S.], indomitable, game to the backbone; inexorable, relentless, not to be shaken, not to be put down; tenax propositi [Lat.]; inflexible etc. (hard) 323; obstinate etc. 606; steady etc. (persevering) 604.1. earnest, serious; set upon, bent upon, intent upon.    steel against, proof against; in utrumque paratus [Lat.].    ... show more

Roget 606: obstinate, tenacious, stubborn, obdurate, casehardened; inflexible etc. (hard) 323; balky; immovable, unshakable, not to be moved; inert etc. 172; unchangeable etc. 150; inexorable etc. (determined) 604; mulish, obstinate as a mule, pig-headed.    dogged; sullen, sulky; unmoved, uninfluenced unaffected.    willful, self-willed, perverse; resty^†, restive, restiff^†; pervicacious^†, wayward, refractory, unruly; heady, headstrong; entete [Fr.]; contumacious; crossgrained^†.    arbitrary, dogmatic, positive, bigoted; prejudiced etc. 481; creed-bound; prepossessed, infatuated; stiff-backed, stiff necked, stiff hearted; hard-mouthed, hidebound; unyielding; impervious, impracticable, inpersuasible^†; unpersuadable; intractable, untractable^†; incorrigible, deaf to advice, impervious to reason; crotchety etc. 608.    ... show more

Impervious to pleas, persuasion, requests, reason:
— Cynthia was inexorable; she would have none of him.

synonyms: adamant, adamantine, intransigent.