relentless

• POS: Adjective
• HYPHEN: re=lent=less

CIDE DICTIONARY

relentless, a. 

 Unmoved by appeals for sympathy or forgiveness; insensible to the distresses of others; destitute of tenderness; unrelenting; unyielding; unpitying; as, a prey to relentless despotism.  [1913 Webster]
"For this the avenging power employs his darts, . . .
Thus will persist, relentless in his ire."  [1913 Webster]

OXFORD DICTIONARY

relentless, adj.
1 unrelenting; insistent and uncompromising.
2 continuous; oppressively constant (the pressure was relentless).

Derivative

relentlessly adv. relentlessness n.

THESAURUS

relentless

adamant, adamantine, ardent, assiduous, bound, bound and determined, bowelless, cast-iron, ceaseless, certain, committed, constant, continual, continuing, continuous, cruel, decided, decisive, dedicated, definite, determined, devoted, diligent, dog-eat-dog, dogged, dour, earnest, enduring, energetic, faithful, fated, fateful, ferocious, fervent, fierce, firm, flinty, fundamentalist, grim, habitual, hard, hard-core, hardworking, harsh, heartless, hidebound, immovable, immutable, implacable, impliable, inalterable, incessant, inclement, indefatigable, indefeasible, indomitable, industrious, inelastic, ineluctable, inescapable, inevasible, inevitable, inexorable, inflexible, inhuman, insistent, intractable, intransigent, invincible, iron, ironbound, ironclad, ironhanded, irreconcilable, irresistible, irrevocable, laborious, lasting, loyal, merciless, mortal, muscle-bound, necessary, never idle, never-tiring, obdurate, obstinate, orthodox, patient, patient as Job, permanent, perpetual, perseverant, persevering, persistent, persisting, pertinacious, pitiless, plodding, plugging, preoccupied, procrustean, purist, puristic, puritan, puritanic, purposeful, rapt, regular, remorseless, resistless, resolute, resolved, rigid, rigorist, rigoristic, rigorous, rock-ribbed, rockbound, ruthless, sedulous, serious, sincere, single-minded, sleepless, slogging, stable, steadfast, steady, steely, stern, stiff, stiff-necked, straightlaced, straitlaced, strenuous, strict, stringent, stubborn, sure, sure as death, sure as fate, tenacious, tireless, tough, unabated, unabating, unaffected, unalterable, unappeasable, unavoidable, unbending, unbroken, unceasing, unchangeable, uncompassionate, uncompassioned, uncompromising, unconquerable, uncontrollable, undaunted, undeflectable, undeviating, undiscouraged, undrooping, unfailing, unfaltering, unfeeling, unflagging, unflinching, unforgiving, ungiving, unintermitting, uninterrupted, unmerciful, unmoved, unmoving, unnodding, unpitiful, unpitying, unpreventable, unrelaxing, unrelenting, unrelieved, unremitting, unremorseful, unsleeping, unsparing, unstoppable, unswerving, unsympathetic, unsympathizing, untiring, unwavering, unwearied, unwearying, unwinking, unyielding, utterly attentive, vehement, weariless, wholehearted, without mercy, zealous

ROGET THESAURUS

relentless

Resolution

N resolution, determination, will, iron will, unconquerable will, will of one's own, decision, resolution, backbone, clear grit, true grit, grit, sand, strength of mind, strength of will, resolve, firmness, energy, manliness, vigor, game, pluck, resoluteness, zeal, aplomb, desperation, devotion, devotedness, mastery over self, self control, self command, self possession, self reliance, self government, self restraint, self conquest, self denial, moral courage, moral strength, perseverance, tenacity, obstinacy, bulldog, British lion, resolved, determined, strong-willed, strong-minded, resolute, self-possessed, decided, definitive, peremptory, tranchant, unhesitating, unflinching, unshrinking, firm, iron, gritty, indomitable, game to the backbone, inexorable, relentless, not to be shaken, not to be put down, tenax propositi, inflexible, obstinate, steady, earnest, serious, set upon, bent upon, intent upon, steel against, proof against, in utrumque paratus, resolutely, in earnest, in good earnest, seriously, joking apart, earnestly, heart and soul, on one's mettle, manfully, like a man, with a high hand, with a strong hand, at any rate, at any risk, at any hazard, at any price, at any cost, at any sacrifice, at all hazards, at all risks, at all events, a' bis ou a blanc, cost what it may, coute, a tort et a travers, once for all, neck or nothing, rain or shine, spes sibi quisque, celui qui veut celui-la peut, chi non s'arrischia non guadagna, frangas non flectes, manu forti, tentanda via est.

Severity

N severity, strictness, harshness, rigor, stringency, austerity, inclemency, arrogance, precisianism, arbitrary power, absolutism, despotism, dictatorship, autocracy, tyranny, domineering, oppression, assumption, usurpation, inquisition, reign of terror, martial law, iron heel, iron rule, iron hand, iron sway, tight grasp, brute force, brute strength, coercion, strong hand, tight hand, hard lines, hard measure, tender mercies, sharp practice, pipe-clay, officialism, tyrant, disciplinarian, precisian, martinet, stickler, bashaw, despot, hard master, Draco, oppressor, inquisitor, extortioner, harpy, vulture, accipitres, birds of prey, raptorials, raptors, severe, strict, hard, harsh, dour, rigid, stiff, stern, rigorous, uncompromising, exacting, exigent, exigeant, inexorable, inflexible, obdurate, austere, hard-headed, hard-nosed, hard-shell, relentless, Spartan, Draconian, stringent, strait-laced, searching, unsparing, iron-handed, peremptory, absolute, positive, arbitrary, imperative, coercive, tyrannical, extortionate, grinding, withering, oppressive, inquisitorial, inclement, cruel, haughty, arrogant, precisian, severely, with a high hand, with a strong hand, with a tight hand, with a heavy hand, at the point of the sword, at the point of the bayonet, Delirant reges plectuntur Achivi, manu forti, ogni debole ha sempre il suo tiranno.

Resentment

N resentment, displeasure, animosity, anger, wrath, indignation, exasperation, bitter resentment, wrathful indignation, pique, umbrage, huff, miff, soreness, dudgeon, acerbity, virulence, bitterness, acrimony, asperity, spleen, gall, heart-burning, heart-swelling, rankling, ill humor, bad humor, ill temper, bad temper, irascibility, ill blood, revenge, excitement, irritation, warmth, bile, choler, ire, fume, pucker, dander, ferment, ebullition, towering passion, acharnement, angry mood, taking, pet, tiff, passion, fit, tantrums, burst, explosion, paroxysm, storm, rage, fury, desperation, violence, fire and fury, vials of wrath, gnashing of teeth, hot blood, high words, scowl, sulks, affront, provocation, offense, indignity, grudge, crow to pluck, bone to pick, sore subject, casus belli, ill turn, outrage, Furies, Eumenides, buffet, slap in the face, box on the ear, rap on the knuckles, angry, wrath, irate, ireful, wrathful, cross, Achillean, sulky, bitter, virulent, acrimonious &c (discourteous), violent, warm, burning, boiling, boiling over, fuming, raging, foaming, foaming at the mouth, convulsed with rage, offended, waxy, acharne, wrought, worked up, indignant, hurt, sore, set against, fierce, wild, rageful, furious, mad with rage, fiery, infuriate, rabid, savage, relentless, flushed with anger, flushed with rage, in a huff, in a stew, in a fume, in a pucker, in a passion, in a rage, in a fury, in a taking, in a way, on one's high ropes, up in arms, in high dudgeon, angrily, in the height of passion, in the heat of passion, in the heat of the moment, Int, tantaene animis coelestibus irae!, marry come up!, zounds!, 'sdeath!, one's blood being up, one's back being up, one's monkey being up, fervens difficili bile jecur, the gorge rising, eyes flashing fire, the blood rising, the blood boiling, haeret lateri lethalis arundo, beware the fury of a patient man, furor arma ministrat, ira furor brevis est, quem Jupiter vult perdere dementat prius, What, drunk with choler?.

Malevolence

N malevolence, bad intent, bad intention, unkindness, diskindness, ill nature, ill will, ill blood, bad blood, enmity, hate, malignity, malice, malice prepense, maliciousness, spite, despite, resentment, uncharitableness, incompassionateness, gall, venom, rancor, rankling, virulence, mordacity, acerbity churlishness, hardness of heart, heart of stone, obduracy, cruelty, cruelness, brutality, savagery, ferity, ferocity, barbarity, inhumanity, immanity, truculence, ruffianism, evil eye, cloven foot, torture, vivisection, ill turn, bad turn, affront, outrage, atrocity, ill usage, intolerance, persecution, tender mercies, unkindest cut of all, malevolent, unbenevolent, unbenign, ill-disposed, ill-intentioned, ill-natured, ill-conditioned, ill-contrived, evil-minded, evil- disposed, black-browed, malicious, malign, malignant, rancorous, despiteful, spiteful, mordacious, caustic, bitter, envenomed, acrimonious, virulent, unamiable, uncharitable, maleficent, venomous, grinding, galling, harsh, disobliging, unkind, unfriendly, ungracious, inofficious, invidious, uncandid, churlish, surly, sullen, cold, cold-blooded, cold-hearted, black-hearted, hard-hearted, flint-hearted, marble-hearted, stony-hearted, hard of heart, unnatural, ruthless, relentless, cruel, brutal, brutish, savage, savage as a bear, savage as a tiger, ferine, ferocious, inhuman, barbarous, barbaric, semibarbaric, fell, untamed, tameless, truculent, incendiary, bloodthirsty, atrocious, bloodyminded, fiendish, fiendlike, demoniacal, diabolic, diabolical, devilish, infernal, hellish, Satanic, Tartaran, malevolently, with bad intent, cruel as death, hard unkindness' alter'd eye, homo homini lupus, mala mens, malus animus, rich gifts wax poor when givers prove unkind, sharp-tooth'd unkindness.

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.

Impenitence

N impenitence, irrepentance, recusance, lack of contrition, hardness of heart, seared conscience, induration, obduracy, impenitent, uncontrite, obdurate, hard, hardened, seared, recusant, unrepentant, relentless, remorseless, graceless, shriftless, lost, incorrigible, irreclaimable, unreconstructed, unregenerate, unreformed, unrepented, unreclaimed, unatoned.