relentless
I
adjective
assiduous, bowel less, brutish, cold, cold-blooded, cold-hearted, continuous, cruel, determined, dictatorial, endless, hard, hard of heart, hardhearted, harsh, heedless, immisericors, impenitent, imperious, implacable, inclement, indefatigable, inexorabilis, inexorable, inflexible, insensitive, insistent, intolerant, intransigent, iron, merciless, obdurate, obstinate, perseverant, persevering, persistent, pertinacious, pitiless, pressing, rancorous, remorseless, resolute, rigid, ruthless, sedulous, severe, steadfast, stern, stony-hearted, stringent, stubborn, tenacious, truculent, tyrannical, unappeasable, unbending, uncompassionate, uncompromising, undaunted, undeviating, unfaltering, unfeeling, unflinching, unforgiving, unintermitting, unmerciful, unmitigable, unmoved by pity, unpitying, unrelenting, unremitting, unshrinking, unsparing, unswerving, unsympathetic, unyielding, vindictive, without regrets
II
index
callous, close (rigorous), cold-blooded, cruel, dictatorial, diligent, draconian, faithful (diligent), immutable, implacable, inexorable, inflexible, ironclad, malicious, obdurate, patient, persistent, pertinacious, recalcitrant, remorseless, resolute, rigid, ruthless, sedulous, serious (devoted), severe, stable, steadfast, unalterable, unbending, uncompromising, unrelenting, unyielding
Burton's Legal Thesaurus.
William C. Burton.
2006