【神秘莫测】〖shén mì mò cè〗[be veiled in mystery; be enveloped in mystery; be rapt [shrouded; wrapped] in mystery]

神仙中人觉先知，

秘而不露才卓识。

莫敢谁何能媲美，

测评睿智古今稀。

使人揣摸不透，难以了解或理解究竟高深到什么程度。make people fathom not transparent, difficult to understand or comprehend　exactly profound reach what degree.同：神乎其神。