ardent assiduous constant continuing diligent dogged enduring energetic faithful fervent going strong hard hardworking immutable in full force in full swing inalterable indefatigable indomitable industrious inexhaustible 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 unabated unabating unallayed unbated unconquerable undaunted undiminished undiscouraged undrooping unexhausted unfaded unfailing unfaltering unflinching unintermitting uninterrupted unnodding unrelaxing unrelenting unremitting unshaken unsleeping unsparing unswerving untiring unwavering unweakened unweakening unwearied unwearying unwinking unwithered unworn utterly attentive vehement weariless zealous