Synonyms and related words :
assiduous, cartilaginous, chewy, cohesive, constant, continuing, coriaceous, dedicated, determined, diligent, dogged, durable, enduring, faithful, fibrous, gristly, hard, hardy, immutable, inalterable, indefatigable, indomitable, industrious, inexhaustible, insistent, invincible, lasting, leatherlike, leathery, loyal, never-tiring, obstinate, patient, patient as Job, permanent, perseverant, persevering, persistent, persisting, pertinacious, plodding, plugging, preoccupied, rapt, relentless, resistant, resolute, ropy, sedulous, sinewy, single-minded, sleepless, slogging, stable, steadfast, steady, stiff, stringy, strong, stubborn, tenacious, tireless, tough, tough as leather, unabating, unconquerable, undaunted, undiscouraged, undrooping, unfailing, unfaltering, unflagging, unflinching, unintermitting, uninterrupted, unnodding, unrelaxing, unrelenting, unremitting, unsleeping, unswerving, unwavering, unwearied, unwearying, unwinking, utterly attentive, vigorous, viscid, weariless, wiry