ex·is·ten·tial·ist /-lɪst/
  存在主義者
  existentialist
       adj : relating to or involving existentialism; "existentialist
             movement"; "existentialist philosophy"; "the
             existentialist character of his ideas"
       n : a philosopher who emphasizes freedom of choice and personal
           responsibility but who regards human existence in a
           hostile universe as unexplainable