sisyphean, heroic, superhuman, monumental, daunting, admirable, titanic, stakhanovite, valiant, mammoth, commendable, gargantuan, tireless, strenuous, gallant, colossal, formidable, prodigious, untiring, superlative, arduous, grueling, stupendous, indefatigable, remarkable, gutsy, laudable, immense, miraculous, backbreaking, staggering, laborious, futile, dauntless, indomitable, inconsiderable, extraordinary, exhausting, feeble, tedious, manful, undaunted, doughty, selfless, masterful, unstinting, frantic, wearisome, surmountable, relentless, quixotic, churchillian, unenviable, elephantine, astonishing, concerted, applaudable, gutty, enormous, epochal, painstaking, unaccomplished, massive, unfathomable, thankless, inspiriting, impressive, perilous, peerless, praiseworthy, ferocious, toilsome, epic, unflagging, marvelous, unglamorous, fearsome, brave, redoubled, resolute, ceaseless, dizzying, unsung, enervating, workmanlike, assiduous, phenomenal, improbable, multifarious, momentous, machinelike, gigantic, nerveless, fruitless, unimaginable, desultory, astounding, sheer, unremitting, weighty, tortuous, brawny, puny, sinewy, enfeebled, stalwart, wiry, lithe, sacrificing

samson

difficult, hard, difficult, hard, powerful, superhuman