'arduous' definitions:

Definition of 'arduous'

From: WordNet
adjective
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" [syn: arduous, backbreaking, grueling, gruelling, hard, heavy, laborious, operose, punishing, toilsome]
adjective
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 [syn: arduous, straining, strenuous]
adjective
Difficult to accomplish; demanding considerable mental effort and skill; "the arduous work of preparing a dictionary"