STRENUOUS

adj. 1 demanding, taxing, tough, arduous, laborious, toilsome, burdensome, tiring, exhausting, difficult, hard, uphill Hauling in the fishing nets was strenuous work 2 energetic, active, vigorous, enthusiastic, zealous, earnest, dynamic, intense, indefatigable, tireless, persistent, dogged, determined, tenacious, pertinacious, resolute, sincere, eager He has made a strenuous effort to be more accommodating