assiduous, constant, continuing, diligent, dogged, enduring, faithful, fixed, immovable, immutable, indefatigable, indomitable, industrious, insistent, invariable, invincible, lasting, loyal, never-tiring, obstinate, patient, patient as Job, permanent, perseverant, persevering, persistent, persisting, pertinacious, plodding, plugging, preoccupied, rapt, relentless, resolute, sedulous, single-minded, sleepless, slogging, stable, steadfast, steady, stubborn, tenacious, tireless, unabating, unalterable, unchangeable, unconquerable, undaunted, undiscouraged, undrooping, unfailing, unfaltering, unflagging, unflinching, unintermitting, uninterrupted, unmodifiable, unmovable, unnodding, unrelaxing, unrelenting, unremitting, unsleeping, unswerving, untiring, unwavering, unwearied, unwearying, unwinking, utterly attentive, weariless