WordNet

resembling an oracle in obscurity of thought; "the oracular sayings of Victorian poets"; "so enigmatic that priests might have to clarify it"; "an enigmatic smile" (同)oracular
not clear to the understanding; "I didnt grasp the meaning of that enigmatic comment until much later"; "prophetic texts so enigmatic that their meaning has been disputed for centuries" (同)enigmatical, puzzling
having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding; "mysterious symbols"; "the mystical style of Blake"; "occult lore"; "the secret learning of the ancients" (同)mystic, mystical, occult, secret, orphic
be uncertain about; think about without fully understanding or being able to decide; "We puzzled over her sudden departure"
a game that tests your ingenuity
a particularly baffling problem that is said to have a correct solution; "he loved to solve chessmate puzzles"; "thats a real puzzler" (同)puzzler, mystifier, teaser
something that baffles understanding and cannot be explained; "how it got out is a mystery"; "it remains one of natures secrets" (同)enigma, secret, closed_book
a story about a crime (usually murder) presented as a novel or play or movie (同)mystery story, whodunit

PrepTutorEJDIC

なぞのような,不可解な
『神秘的な』,不思議な / 理解(説明)しがたい,不可解な,なぞの
《単数形で》(頭を)『悩ませる物』(『事』,『人』),難問,難物 / 《しばしば複合語で用いて》(遊び用の)『パズル』,判じ物,なぞ / 〈難問が〉〈人〉‘の'頭を悩ませる;(…について)〈頭〉をひねって考える《+『名』+『about』(『over』)+『名』》 / (…に)頭を悩ませる,(…を)頭をひねって考える《+『about』(『as to, over』)+『名』》
〈C〉『神秘的な物』(『事』) / 〈C〉好寄心(気がかり)を起こさせる物(事) / 〈C〉推理小説(劇,映画) / 〈U〉『神秘[性]』 / 〈C〉《複数形で》(宗数的)秘法,秘教;(古代ギリシア・ローマの)神秘儀式
(特に)解きにくいなぞ;不可解なこと(もの,人)