Definition of knotty:
complex, preserve, mired, intricate, convolute, snarly, toughened, involved, simple, incomprehensible, difficult, problematical, knotted, tortuous, tangled, voluminous, subtle, crooked, debatable, elaborate, involute, joinery, sawdust, sturdy, contorted, winding, ruffianly, bad, season, confusing, gnarled, labyrinthine, mortise, mortice, carpentry, confused, hard, snarled, problematic, dovetail, daedal, baffling, twisting, elusive, twisty, Daedalian, sand, Byzantine, convoluted, gnarly, knobbed.
difficult (part of speech: adjective)
But before they had settled the knotty point, the engine- driver, growing tired of waiting, let off a shrill whistle from his engine and with the sound the little sleeper stirred, opened her eyes, and sat up suddenly.- "The Story of Jessie", Mabel Quiller-Couch.
- "Memoir, Correspondence, And Miscellanies, From The Papers Of Thomas Jefferson", Thomas Jefferson.
- "Nooks and Corners of the New England Coast", Samuel Adams Drake.