enigma/ɪˈnɪgmə; ɪ`nɪɡmə/ nquestion, person, thing, circumstance, etc that is difficult to understand; mystery 难於理解的问题、 人、 物、 情况等; 奥秘 I've known him for many years, but he remains something of an enigma to me. 我与他相识多年, 他仍然难以捉摸.
牛津英汉双解词典