adj .
hard to understand ; over one's head 이해하기 어려운 ; ~에게 이해되지 않는

• The philosopher's thesis was so _____ that I couldn't get past the first two sentences.
• Every now and then the professor would lift his head from his desk and deliver some _____ pronouncement that left us scratching our heads and trying to figure out that he meant.
• The scholarly journal was so _____ as to be utterly incomprehensible.
  그 학술지는 너무나 난해해서 아예 이해가 불가능할 정도였다.