Synonyms and related words :
Chinese puzzle, Rube Goldberg contraption, can of worms, complex, crux, dilemma, enigma, jungle, knot, knotty point, labyrinth, maze, meander, mesh, mess, node, nodus, nonplus, oxymoron, paradox, perplex, perplexity, pons asinorum, poser, puzzle, quandary, ravel, snafu, snake pit, snarl, tangle, tangled skein, teaser, vexed question, webwork, wheels within wheels, wilderness