THESAURUS
implacable
adamant, adamantine, avenging, cast-iron, cruel, dour, firm, flinty, grim, grudgeful, hard, hard-core, immovable, immutable, impliable, inelastic, inexorable, inflexible, intractable, intransigent, iron, irreconcilable, merciless, mortal, pitiless, punitive, punitory, rancorous, relentless, retaliatory, revanchist, revengeful, rigid, rigorous, rock-ribbed, ruthless, steely, stern, stiff, unaffected, unalterable, unappeasable, unbending, unchangeable, uncompassionate, uncompromising, unflinching, unforgiving, ungiving, unmoved, unrelenting, unsympathetic, unyielding, vengeful, vindicatory, vindictive
ROGET THESAURUS
implacable
Hate
N
hate, hatred, vials of hate, disaffection, disfavor, alienation, estrangement, coolness, enmity, animosity, umbrage, pique, grudge, dudgeon, spleen bitterness, bitterness of feeling, ill blood, bad blood, acrimony, malice, implacability, repugnance, misanthropy, demonophobia, gynephobia, negrophobia, odium, unpopularity, detestation, antipathy, object of hatred, object of execration, abomination, aversion, b=ete noire, enemy, bitter pill, source of annoyance, hating, abhorrent, averse from, set against, bitter,
implacable, unloved, unbeloved, unlamented, undeplored, unmourned, uncared for, unendeared, un-valued, disliked, crossed in love, forsaken, rejected, lovelorn, jilted, obnoxious, hateful, odious, abominable, repulsive, offensive, shocking, disgusting, reprehensible, invidious, spiteful, malicious, insulting, irritating, provoking, at daggers drawn, not on speaking terms, at loggerheads, no love lost between.
Revenge
N
revenge, revengement, vengeance, avengement, avengeance, sweet revenge, vendetta, death feud, blood for blood retaliation, day of reckoning, rancor, vindictiveness, implacability, malevolence, ruthlessness, avenger, vindicator, Nemesis, Eumenides, revengeful, vengeful, vindictive, rancorous, pitiless, ruthless, rigorous, avenging, unforgiving, unrelenting, inexorable, stony-hearted,
implacable, relentless, remorseless, aeternum servans sub pectore vulnus, rankling, immitigable, manet ciratrix, manet alid mente repostum, dies irae dies illa, in high vengeance there is noble scorn, inhumanum verbum est ultio, malevolus animus abditos dentes habet, now infidel I have thee on the hip.