Synonyms and related words :
assiduous, audacious, bold, constant, continuing, courageous, dauntless, diligent, dogged, enduring, faithful, fearless, immutable, inalterable, indefatigable, indomitable, industrious, insistent, intrepid, 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, unabashed, unabating, unappalled, unawed, unblenching, unblinking, unconquerable, uncowed, uncringing, undiscouraged, undismayed, undrooping, unfailing, unfaltering, unflagging, unflinching, unintermitting, uninterrupted, unintimidated, unnodding, unrelaxing, unrelenting, unremitting, unshrinking, unsleeping, unswerving, untiring, unwavering, unwearied, unwearying, unwinking, utterly attentive, valiant, valorous, weariless