Meaning : Characterized by effort to the point of exhaustion. Especially physical effort.
Example :
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.
Synonyms : arduous, backbreaking, grueling, gruelling, hard, heavy, laborious, punishing, toilsome