1. arduous, backbreaking, grueling, gruelling, hard, heavy, laborious, operose, punishing, toilsome

characterized by effort to the point of exhaustion; especially physical effort

Example Sentences:
'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
• operose
• punishing
• toilsome