inaccessible

a. 难接近的,难达到的,难达成的

The scientist discovered the plant in the most inaccessible reaches of the jungle.

这位科学家在丛林深处最难进入的区域发现了这种植物。

His busy schedule made him completely inaccessible to his students.

他的时间排得很满，学生根本无法和他接触。