fathomless

1. ADJ Something that is fathomless cannot be measured or understood because it gives the impression of being very deep, mysterious, or complicated. 深不可测的; 不能理解的

...the fathomless space of the universe. ...深不可测的宇宙空间。

The silence was fathomless and overwhelming. 这样的沉静不能测透、侵袭着一切。