Making great mental demands; hard to comprehend or solve or believe:
— I faced the knotty problem of what to have for breakfast.

synonyms: baffling, elusive, problematic, problematical, tough.

Polish: problematyczny

Used of old persons or old trees; covered with knobs or knots.

synonyms: gnarled, gnarly, knobbed, knotted.

Roget 704: difficult, not easy, hard, tough; troublesome, toilsome, irksome; operose^†, laborious, onerous, arduous, Herculean, formidable; sooner said than done; more easily said than done, easier said than done.    difficult to deal with, hard to deal with; ill-conditioned, crabbed, crabby; not to be handled with kid gloves, not made with rose water.    awkward, unwieldy, unmanageable; intractable, stubborn etc. (obstinate) 606; perverse, refractory, plaguy^†, trying, thorny, rugged; knotted, knotty; invious^†; pathless, trackless; labyrinthine etc. (convoluted) 248; intricate, complicated etc. (tangled) 59; impracticable etc. (impossible) 471; not feasible etc. 470; desperate etc. (hopeless) 859.    embarrassing, perplexing etc. (uncertain) 475; delicate, ticklish, critical; beset with difficulties, full of difficulties, surrounded by difficulties, entangled by difficulties, encompassed with difficulties.    under a difficulty; in a box; in difficulty, in hot water, in the suds, in a cleft stick, in a fix, in the wrong box, in a scrape etc. n., in deep water, in a fine pickle; in extremis; between two stools, between Scylla and Charybdis; surrounded by shoals, surrounded by breakers, surrounded by quicksands; at cross purposes; not out of the wood.    reduced to straits; hard pressed, sorely pressed; run hard; pinched, put to it, straitened; hard up, hard put to it, hard set; put to one's shifts; puzzled, at a loss, etc. (uncertain) 475; at the end of one's tether, at the end of one's rope, at one's wit's end, at a nonplus, at a standstill; graveled, nonplused, nonplussed, stranded, aground; stuck fast, set fast; up a tree, at bay, aux abois [Fr.], driven into a corner, driven from pillar to post, driven to extremity, driven to one's wit's end, driven to the wall; au bout de son Latin; out of one's depth; thrown out.    accomplished with difficulty; hard-fought, hard-earned.    ... show more

Roget 321: dense, solid; solidified etc. v.; caseous; pukka^†; coherent, cohesive etc. 46; compact, close, serried, thickset; substantial, massive, lumpish^†; impenetrable, impermeable, nonporous, imporous^†; incompressible; constipated; concrete etc. (hard) 323; knotted, knotty; gnarled; crystalline, crystallizable; thick, grumous^†, stuffy.    undissolved, unmelted^†, unliquefied^†, unthawed^†.    indivisible, indiscerptible^†, infrangible^†, indissolvable^†, indissoluble, insoluble, infusible.    ... show more

Polish: sękaty

Highly complex or intricate and occasionally devious:
— A knotty problem.

synonyms: Byzantine, convoluted, involved, tangled, tortuous.

Tangled in knots or snarls.

synonyms: snarled, snarly.

Polish: zawęźlony, zasupłany