| oracle(difficulty, question, secret, puzzle, subtlety) |
| perplexity(noun, difficulty, question, secret, puzzle) |
| poser(difficulty, question, secret, puzzle, subtlety) |
| problem(difficulty, question, secret, puzzle, obscurity) |
| puzzle(difficulty, question, secret, obscurity, mystery) |
| puzzlement(question, secret, puzzle, obscurity, subtlety) |
| question(difficulty, secret, puzzle, obscurity, subtlety) |
| rebus(difficulty, question, secret, puzzle, subtlety) |
| riddle(difficulty, question, secret, puzzle, obscurity) |
| rune(difficulty, question, secret, puzzle, subtlety) |
| secrecy(difficulty, question, secret, puzzle, obscurity) |
| secret(question, puzzle, perplexity, obscurity, subtlety) |
| sphinx(difficulty, question, secret, puzzle, perplexity) |
| stickler(difficulty, question, secret, puzzle, obscurity) |
| stumper(difficulty, question, secret, puzzle, perplexity) |
| subtlety(difficulty, question, secret, puzzle, obscurity) |
| teaser(difficulty, question, secret, puzzle, perplexity) |
| thriller(difficulty, question, secret, puzzle, subtlety) |
| twister(difficulty, question, secret, puzzle, obscurity) |
| whodunit(difficulty, question, secret, puzzle, subtlety) |