onerous Synonyms

taxing difficult wearing demanding burdensome back-breaking unwieldy trying troublesome tough toilsome tiring tedious time-consuming superincumbent strenuous severe uphill upstream heavy-handed effortful heavier gruelling grueling backbreaking worrisome weighty wearying wearisome vexatious rugged rigorous hard grinding grievous formidable fatiguing exigent exhausting exacting arduous cumbersome crushing challenging harsh heavy punishing ponderous painful overburdensome