difficult

1 requiring considerable physical or mental effort <difficult questions on the exam that required analytical thinking> Synonyms arduous, Augean, backbreaking, challenging, demanding, hard, 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

2 requiring exceptional skill or caution in performance or handling <it's a difficult situation when two of your friends are quarreling and you're trying to stay out of it> Synonyms catchy, delicate, tricky, dodgy [chiefly British], hairy, knotty, nasty, prickly, problematic (also problematical), sensitive, spiny, sticky, thorny, ticklish, touchy, tough, tricksyRelated Words abstract, abstruse, complex, complicated, hard, intricate, involved, recondite, serious; problem, scabrous, stubborn, troublesome, troublous, vexatious, vexing, worrisome; burdensome, demanding, discommoding, exacting, exhausting, importunate, inconvenient, onerous, oppressive, painful, stressfulNear Antonyms easy, effortless, manageable, painless, simple, straightforward, uncomplicated, undemanding, unproblematic