backbreaking Synonyms

arduous heavy toilsome hard laborious grueling gruelling operose punishing rugged taxing superincumbent rough strenuous sticky sisyphean serious severe thorny effortful brain surgery laboured weighty walrus uphill trying troublesome tricky tough toilful tiring profound ponderous plodding exhausting exacting draining difficult demanding crushing complicated cloggy clayey ceramic burdensome formidable grave grievous painful oppressive