[{"Bold_text": "noun", "List Items": ["a puzzling or inexplicable occurrence or situation:His disappearance is an enigma that has given rise to much speculation.Synonyms: problem", "a person of puzzling or contradictory character:To me he has always been an enigma, one minute completely insensitive, the next moved to tears.", "a saying, question, picture, etc., containing a hidden meaning; riddle.", "(initial capital letter)a German-built enciphering machine developed for commercial use in the early 1920s and later adapted and appropriated by German and other Axis powers for military use through World War II."]}]