Synonyms and related words :
Herculean, annoying, arduous, besetting, bothersome, burdensome, crushing, effortful, forced, grueling, hard-earned, hard-fought, heavy, hefty, irksome, killing, labored, laborious, onerous, operose, oppressive, painful, plaguey, punishing, strained, strenuous, toilsome, tough, troublesome, trying, uphill, vexatious, wearisome