不可捉摸

Explanation: Fathom: speculation expected. Refers to the person or thing can not guess and estimate. 　　Usage: Partial official; as the predicate attribute; for human nature and the speculation of things 　　Source: Mingxie Zhao Zhe, "the Ministry of Four people Five Miscellaneous ZU": "and a clo_set_ full, not from the back, but it is evasive words to cover it." 　　Examples: However, this clip was chewing meat and rice, are intangible like some of the secrets of his mouth. (Lao She, "Master said Zhao," XVIII) 　　Riddle: Hedgehog; prohibit fishing of fish and shrimp Thesaurus:  not know why it is so, extremely puzzled; be completely confused, mystery of mysteries— — extremely mysterious and abstruse, Figure it out, Puzzling, fathomless, Up on things vain, Couldn't find north, Touch door vain, cannot distinguish whether it's genuine or fake,true or false, perplex Antonym Group:  deafening noise, Fakuizhenlong