"arduous" in the adjective 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"

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

3. arduous

difficult to accomplish demanding considerable mental effort and skill

"the arduous work of preparing a dictionary"

Source: WordNet® (An amazing lexical database of English)

Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.

View WordNet® License