Synonyms of arduous

Adjective

1. arduous, backbreaking, grueling, gruelling, hard, heavy, laborious, operose, punishing, toilsome, effortful (vs. effortless)

usage: characterized by effort to the point of exhaustion; especially physical effort; "worked their arduous way up the mining valley"; "a grueling campaign"; "hard labor"; "heavy work"; "heavy going"; "spent many laborious hours on the project"; "set a punishing pace"

2. arduous, straining, strenuous, effortful (vs. effortless)

usage: taxing to the utmost; testing powers of endurance; "his final, straining burst of speed"; "a strenuous task"; "your willingness after these six arduous days to remain here"- F.D.Roosevelt

3. arduous, difficult (vs. easy), hard

usage: difficult to accomplish; demanding considerable mental effort and skill; "the arduous work of preparing a dictionary"

Definition and meaning of arduous (Dictionary)