Antonyms of adj arduous

3 senses of arduous

Sense 1
arduous, 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 punishing pace")

INDIRECT (VIA effortful) -> effortless -- (requiring or apparently requiring no effort; "the swallows glided in an effortless way through the busy air")

Sense 2
arduous, 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)

INDIRECT (VIA effortful) -> effortless -- (requiring or apparently requiring no effort; "the swallows glided in an effortless way through the busy air")

Sense 3
arduous -- (difficult to accomplish; demanding considerable mental effort and skill; "the arduous work of preparing a dictionary")

INDIRECT (VIA difficult) -> easy -- (posing no difficulty; requiring little effort; "an easy job"; "an easy problem"; "an easy victory"; "the house is easy to heat"; "satisfied with easy answers"; "took the easy way out of his dilemma")

Similarity of adj arduous

3 senses of arduous

Sense 1
arduous, 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 punishing pace")
       => effortful (vs. effortless) -- (requiring great physical effort)

Sense 2
arduous, 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)
       => effortful (vs. effortless) -- (requiring great physical effort)

Sense 3
arduous -- (difficult to accomplish; demanding considerable mental effort and skill; "the arduous work of preparing a dictionary")
       => difficult (vs. easy), hard -- (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?")