Словарь синонимов английского языка - tireless

(adj) energetic, vital, vigorous, dynamic, spirited, lively, indefatigable, hardworking, industrious, untiring, unflagging, unfaltering, unfailing, persistent, dogged, tenacious, pertinacious, persevering, staunch, sedulous, unwavering, unswerving, undeviating, steady, steadfast, resolute, determined: We all appreciate the honorary secretary's tireless efforts on behalf of our fund-raising this year.