Herculean, aggravating, annoying, arduous, backbreaking, black, bleak, boresome, boring, bothering, bothersome, burdensome, crushing, dark, dismal, disturbing, draining, drear, drearisome, dreary, effortful, exasperating, exhausting, fatiguesome, fatiguing, forced, funebrial, funereal, galling, gloomy, grave, gray, grim, grueling, harassing, hard-earned, hard-fought, heavy, hefty, importunate, importune, irking, irksome, irritating, killing, labored, laborious, onerous, operose, oppressive, painful, pesky, pestering, pestiferous, pestilent, pestilential, plaguesome, plaguey, plaguing, provoking, punishing, saturnine, solemn, somber, sombrous, strained, straining, strenuous, stressful, stupefyingly boring, stuporific, teasing, tiresome, tiring, toilsome, tormenting, tough, triste, troublesome, troubling, trying, uphill, vexatious, vexing, weariful, wearing, weary, wearying, worrisome, worrying, yawny