noun. One that is puzzling, ambiguous, or inexplicable.

noun. A perplexing speech or text; a riddle.

noun. A dark saying or representation, in which some known thing is concealed under obscure words or forms; a question, saying, figure, or design containing a hidden meaning which is proposed for discovery; a riddle.

noun. Anything inexplicable to an observer, such as the means by which something is effected, the motive for a course of conduct, the cause of a phenomenon, etc.: as, how it was done is an enigma; his conduct is to me an enigma.

noun. A dark, obscure, or inexplicable saying; a riddle; a statement, the hidden meaning of which is to be discovered or guessed.

noun. An action, mode of action, or thing, which cannot be satisfactorily explained; a puzzle.

noun. Something puzzling, mysterious or inexplicable.

noun. A riddle, or a difficult problem.

noun. a difficult problem

noun. something that baffles understanding and cannot be explained

"Suffice it to say here that this triple enigma is as comforting as wine and open as an English fireside; that this thing that bewilders the intellect utterly quiets the heart: but out of the desert, from the dry places and, the dreadful suns, come the cruel children of the lonely God; the real Unitarians who with scimitar in hand have laid waste the world."

Enigma machine  a riddle wrapped up in an enigma  enigmatic  

perplexity  problem  

sigma  stigma  

anachronism  anomaly  compulsion  conundrum  dilemma  

Chinese puzzle  Gordian knot  arcanum  baffle  bafflement