| whodunit(noun, question, secret, puzzle, dilemma) |
| brainteaser(noun, difficulty, difficult, issue, challenge) |
| teaser(noun, difficulty, difficult, issue, challenge) |
| head-scratcher(noun, trouble, difficult, issue, challenge) |
| labyrinth(noun, secret, brain, twister, brain-twister) |
| mystery story(noun, expression, idiom, question, secret) |
| bewilderment(noun, question, secret, dilemma, mystery) |
| tough nut to crack(noun, expression, question, secret, puzzle) |
| cipher(noun, confidence, secret, mystery, brain-twister) |
| code(noun, confidence, secret, mystery, cipher) |
| crossword(noun, difficult, issue, question, task) |
| crossword puzzle(noun, expression, idiom, difficult, issue) |
| cryptogram(noun, difficulty, question, secret, puzzle) |
| difficulty(noun, trouble, difficult, issue, challenge) |
| fair question(noun, expression, idiom, question, secret) |
| maze(noun, secret, brain, twister, brain-twister) |
| sphinx(noun, difficulty, question, secret, puzzle) |
| twister(noun, difficulty, difficult, issue, challenge) |
| anagram(noun, question, problem, secret, puzzle) |
| bone of contention(noun, expression, idiom, question, secret) |