unflagging

showing no signs of weariness even after long hard effort being rewarded for the unflagging zeal with which she led the fund-raising campaign Synonyms indefatigable, inexhaustible, tireless, untiring, wearilessRelated Words assiduous, conscientious, diligent, meticulous, painstaking, sedulous; determined, dogged, patient, persevering, persistent, pertinacious, plodding, relentless, steadfast, steady, stubborn, tenacious, unabating, unfailing, unfaltering, unflinching, unrelenting, unremitting, unwavering; active, busy, dynamic, energetic, feverish, spirited, vigorous; hard, industrious, intense, laborious, slavish, strenuousNear Antonyms indolent, lackadaisical, laggard, lazy, listless, shiftless, slothful, sluggish; apathetic, casual, desultory, languid, spiritless; beat, broken, burned-out (or burnt-out), done in, drained, enervated, jaded, overtaxed, overworked, played out, sapped, spent, tuckered (out), wearied, worn-out