EnglishMerriam-Webster Dictionary
adamant, adamantine, determined, dogged, firm, relentless, resolved, single-minded, steadfast, stubborn, tenacious, unbending, unflinching austere, demanding, flinty, grim, hard, hardened, hard-hearted, harsh, ironbound, severe, stern, tough easy, easygoing, gentle, indulgent, kindly, lenient, merciful, mild, pampering, soft, spoiling, tolerant 3 requiring considerable physical or mental effort //the new recruits had to adjust themselves to the exacting discipline of military life arduous, Augean, backbreaking, challenging, demanding, difficult, effortful, formidable, grueling (
or gruelling)
, hard, heavy, hellacious, herculean, killer, laborious, moiling, murderous, pick-and-shovel, rigorous, rough, rugged, severe, stiff, strenuous, sweaty, tall, testing, toilsome, tough, uphill abstract, abstruse, complex, complicated, elusive, hairy, insoluble, intricate, involved, knotty, opaque, problematic (
also close, conscientious, exact, fussy, meticulous, painstaking, punctilious, scrupulous, undeviating adamant, adamantine, determined, dogged, firm, relentless, resolved, single-minded, steadfast, stubborn, tenacious, unbending, unflinching austere, demanding, flinty, grim, hard, hardened, hard-hearted, harsh, ironbound, severe, stern, tough easy, easygoing, gentle, indulgent, kindly, lenient, merciful, mild, pampering, soft, spoiling, tolerant 3 requiring considerable physical or mental effort //the new recruits had to adjust themselves to the exacting discipline of military life arduous, Augean, backbreaking, challenging, demanding, difficult, effortful, formidable, grueling (
or gruelling)
, hard, heavy, hellacious, herculean, killer, laborious, moiling, murderous, pick-and-shovel, rigorous, rough, rugged, severe, stiff, strenuous, sweaty, tall, testing, toilsome, tough, uphill abstract, abstruse, complex, complicated, elusive, hairy, insoluble, intricate, involved, knotty, opaque, problematic (
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