gruelling Synonyms

backbreaking exhausting heavy toilsome taxing laborious hard operose grueling punishing arduous stiff strenuous stressful severe tedious straining testing effortful easier said than done back-breaking wearying wearisome wearing uphill trying tough tiresome tiring rigorous punitory exacting draining disciplinary difficult devastating demanding crippling clayey challenging annoying fatiguing forced penological painful onerous labored killing impenetrable hellish