definition of
[arduous]

[1] #1 arduous s. [backbreaking, grueling, gruelling, hard, heavy, laborious, operose, punishing, toilsome] 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 punishin. wn

[2] #2 arduous s. [straining, strenuous] 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. wn

[3] #3 arduous s. difficult to accomplish; demanding considerable mental effort and skill; "the arduous work of preparing a dictionary". wn