ardent assiduous constant continuing diligent dogged enduring energetic faithful fervent hard hardworking immutable inalterable indefatigable indomitable industrious insistent invincible laborious lasting loyal never idle 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 strenuous stubborn tenacious tireless unabating unconquerable undaunted undiscouraged undrooping unexhausted unfailing unfaltering unfatigued unflagging unflinching unintermitting uninterrupted unnodding unrelaxing unrelenting unremitting unsleeping unsparing unswerving untired untiring unwavering unwearying unwinking utterly attentive vehement weariless zealous