| Arduous 1. (a.) Steep and lofty, in a literal sense; hard to climb. 2. (a.) Attended with great labor, like the ascending of acclivities; difficult; laborious; as, an arduous employment, task, or enterprise. Thesaurus Entries Herculean, abrupt, abstruse, backbreaking, brutal, burdensome, complex, critical, crushing, delicate, demanding, difficile, difficult, effortful, energetic, exacting, exhausting, fatiguing, forced, formidable, grueling, hairy, hard, heavy, hefty, intricate, jawbreaking, killing, knotted, knotty, labored, laborious, mean, no picnic, not easy, onerous, operose, oppressive, painful, precipitate, precipitous, punishing, rigorous, rough, rugged, set with thorns, severe, sheer, sideling, spiny, steep, stickle, strained, strenuous, taxing, thorny, ticklish, tiring, toilsome, tough, tricksy, tricky, troublesome, trying, uphill, vigorous, wearisome, wicked |