grueling

1 requiring considerable physical or mental effort running a marathon is grueling Synonyms arduous, Augean, backbreaking, challenging, demanding, difficult, effortful, exacting, formidable, hard (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

2 requiring much time, effort, or careful attention cutting diamonds can be grueling work Synonyms arduous, burdensome, challenging, exacting, demanding (or gruelling), killing, laborious, onerous, persnickety, taxing, toilsomeRelated Words difficult, formidable, hard, herculean, rough, rugged, stiff, strenuous, testing, tough; oppressive, trying; rigid, rigorous, severe, stern, strict, stringentNear Antonyms easy, effortless, facile, simple, smoothAntonyms light, nondemanding, unchallenging, undemanding