| cryptogram(difficulty, question, secret, puzzle, obscurity) |
| difficulty(question, secret, puzzle, obscurity, subtlety) |
| grabber(difficulty, question, secret, puzzle, perplexity) |
| inscrutability(difficulty, question, secret, puzzle, subtlety) |
| inscrutableness(difficulty, question, secret, puzzle, subtlety) |
| mindboggler(difficulty, question, secret, puzzle, subtlety) |
| monogram |
| mystification(question, secret, puzzle, obscurity, subtlety) |
| nut to crack(expression, idiom, secret) |
| occult(difficulty, question, secret, puzzle, subtlety) |
| oracle(difficulty, question, secret, puzzle, subtlety) |
| perplexity(noun, difficulty, question, secret, puzzle) |
| picture puzzle(expression, idiom) |
| poser(noun, question, secret, puzzle, subtlety) |
| puzzlement(question, secret, puzzle, obscurity, subtlety) |
| question(difficulty, secret, puzzle, obscurity, subtlety) |
| rebuses |
| rune(difficulty, question, secret, puzzle, subtlety) |
| secrecy(difficulty, question, secret, puzzle, obscurity) |
| secret(question, puzzle, perplexity, obscurity, subtlety) |