arduous

adjectives

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"

arduous, backbreaking, grueling, gruelling, hard, heavy, laborious, operose, punishing, toilsome

is derived from

arduousness

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

arduous, straining, strenuous

is derived from

arduousness

difficult to accomplish; demanding considerable mental effort and skill

"the arduous work of preparing a dictionary"

arduous

is derived from

arduousness

is similar to

not easy; requiring great physical or mental effort to accomplish or comprehend or endure

"a difficult task"; "nesting places on the cliffs are difficult of access"; "difficult times"; "why is it so hard for you to keep a secret?"

difficult, hard