relentless

Synonyms

determined, dogged, grim, implacable, unappeasable, unflinching, unrelenting, unyielding;

Near Antonyms

slackening, softening, yielding;

impotent, invertebrate, slack, spineless, weak;

complaisant, obliging, pliable, pliant;

Related Words

persevering, persistent, tenacious;

hard, hardheaded, headstrong, intractable, mulish, obdurate, opinionated, peevish, pertinacious, perverse, pigheaded, self-willed, stubborn, uncooperative, willful (or wilful);

merciless, ruthless, unforgiving;