What does "arduous" mean?

Needing or using up much energy; testing powers of endurance.

What is a synonym for "arduous"?

Common synonyms include: strenuous, abrupt, abstruse, agonizing, anguishing, augean.

Pronounced //ˈɑː.djuː.əs//.

/ˈɑː.djuː.əs/ adj

adj ·Common ·High school level

Adjective

1
Needing or using up much energy; testing powers of endurance.
"The movement towards a peaceful settlement has been a long and arduous political struggle."
2
burning; ardent obsolete
"1805-1814, Dante, Henry Francis Cary (translator), The Divine Comedy Where flames the arduous Spirit of Isidore."
3
Difficult or exhausting to traverse.
"Beyond the river, an arduous slope rises 3286 feet in 13 miles."

Adjective

1
difficult to accomplish; demanding considerable mental effort and skill wordnet
2
characterized by effort to the point of exhaustion; especially physical effort wordnet
3
taxing to the utmost; testing powers of endurance wordnet

"She went through a long and arduous vocational course."

From Latin arduus (“lofty, high, steep, hard to reach, difficult, laborious”), akin to Irish ard (“high”).