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