Definition of difficult:
ticklish, concentrated, subtle, balky, unmanageable, confusing, exacting, wayward, incomprehensible, challenging, heavy, profound, Gargantuan, immense, hidden, labored, steep, weighty, vexed, awkward, taxing, careful, stiff, exhausting, backbreaking, contrarious, hard, unfathomable, tedious, trackless, problematic, unenviable, tall, arduous, concealed, incommodious, support, manageable, rocky, perverse, loose, voiceless, painful, digressive, sticky, fractious, unvoiced, digressive, unintelligible, hairy, uncorrectable, dark, inscrutable, serious, strong, stubborn, troublesome, tough, exigent, pathless, metaphysical, occult, mystifying, inconceivable, catchy, deep, equivocal, unyielding, easy, recondite, meandering, mystical, hard-fought, nasty, labyrinthine, simple, unaccountable, tangled, knockout, ambitious, embarrassing, unknown, ornery, unclear, turgid, abstract, titanic, inexplicable, impossible, comfort, rambling, rough, problematical, irksome, paradoxical, attitude, effortful, rigorous, obstinate, rugged, baffling, froward, clear, irritable, tricky, intemperate, inconvenient, vexatious, delicate, herculean, trying, thorny, uncontrollable, enigmatic, tight, punishing, unwieldy, esoteric, gruelling, ambiguous, surd, knotty, grueling, operose.
- adverse (part of speech: adjective)
difficult (part of speech: adjective)
- complex (part of speech: adjective)