Словарь синонимов английского языка - arduous

(adj) 1. laborious, difficult, hard, tough, strenuous, onerous, burdensome, back-breaking, painful, Formal operose; tiring, ehhausting, wearisome, fatiguing, taxing, gruelling, drying, formidable: The Sherpas were well equipped for the arduous climb. What an arduous task it is to read the proofs of a dictionary! 2. energetic, strenuous, vigorous: Montrose made arduous efforts to reconstbuct his army.