Synonyms and related words :
Chinese puzzle, baffling problem, bone of contention, brain twister, catechism, cross-interrogatory, cross-question, crossword puzzle, crux, debating point, demand, enigma, enigmatic question, feeler, floorer, inquiry, interrogation, interrogative, interrogatory, issue, jigsaw puzzle, knot, knotty point, leader, leading question, mind-boggler, moot point, mystery, nut to crack, perplexed question, perplexity, point at issue, point in question, poser, problem, puzzle, puzzlement, puzzler, query, question, question at issue, quodlibet, sixty-four dollar question, sticker, stumper, topic, tough proposition, trial balloon, vexed question, why