The definition of enigma is something or someone that is puzzling or a riddle. The word "enigma" first appeared in print in 1449. Its origins remain as mysterious as the word itself. It is likely to derive from the Latin ænigma, meaning a riddle, or the Greek, ainigma, which derives from the word ainissesthai, "to speak obscurely, speak in riddles."
The definition of a secret is something kept from public knowledge or the knowledge of a specific person.
Find another word for closed-book. In this page you can discover 3 synonyms, antonyms, idiomatic expressions, and related words for closed-book, like: mystery, enigma and secret.