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ENIGMA, a riddle or puzzle, especially a form of verse or prose composition in which the answer is concealed by means of metaphors. Such were the famous riddle of the Sphinx and the riddling answers of the ancient oracles. The composition of enigmas was a favorite amusement in Greece and prizes were often given at banquets for the best solution of them (Athen. x. 457). In France during the 17th century enigma-making became fashionable. Boileau, Charles Riviere Dufresny and J. J. Rousseau did not consider it beneath their literary dignity. The word is applied figuratively to anything inexplicable or difficult of understanding.

noun
1) An obscure or ambiguous saying; especially, a statement or question the meaning of which must be guessed or discovered; a riddle.

“Problems and enigmas which at thirty I fancied I might be able to solve, I find at sixty I must be satisfied simply to propound.” - W.R. Greg “Enigmas of Life”

2) Any act, process, or phenomenon that puzzles or baffles; anything insolvable or inexplicable.

“Machiavelli ... seems to be an enigma - a grotesque assemblage of incongruous qualities.” - Macaulay “Essays, Machiavelli”

SYNONYMS: riddle