backbreaking

requiring considerable physical or mental effort modern machinery has significantly eased the backbreaking work of farming Synonyms arduous, Augean, hard, challenging, demanding, difficult, effortful, exacting, formidable, grueling (or gruelling), heavy, hellacious, herculean, killer, laborious, moiling, murderous, pick-and-shovel, rigorous, rough, rugged, severe, stiff, strenuous, sweaty, tall, testing, toilsome, tough, uphillRelated Words abstract, abstruse, complex, complicated, elusive, hairy, insoluble, intricate, involved, knotty, opaque, problematic (also problematical), recondite, serious, spiny, stubborn, thorny, ticklish, tricky; bruising, burdensome, exhausting, labored, onerous, oppressive, stressful, taxing, tight, trying; annoying, bothersome, distressing, irksome, troublesome, vexatious; grievous, grim, strict, stringent; brutal, cruel, inhuman, painfulNear Antonyms achievable, clear, doable, elementary, manageable, uncomplicated; comforting, gentle, painless, relaxed, smooth, soothing; accessible, friendly, idiotproof, user-friendlyAntonyms cheap, easy, effortless, facile, light, mindless, simple, soft, undemanding