What is another word for riddle of the sphinx?
Pronunciation: [ɹˈɪdə͡l ɒvðə sfˈɪŋks] (IPA) 
The Riddle of the Sphinx is a popular phrase that has made its way into the English language as a metaphor for a difficult or puzzling question. There are numerous ways to refer to this famous enigma. Some possible synonyms for the Riddle of the Sphinx might include perplexity, conundrum, mystery, puzzle, enigma, or brain-teaser. These terms all suggest that the answer to a particular question might be elusive or difficult to grasp, and that some degree of mental effort or contemplation may be required to unravel the solution. Regardless of the terminology used, the Riddle of the Sphinx remains an enduring symbol of intellectual challenge and complexity.
