In·ef·fa·ble

Too great or extreme to be expressed or described in words; beyond verbal expression.

Relating to that which transcends language, often invoking awe, mystery, or the divine.

"They stood at the mountain’s summit in silent reverence, overwhelmed by the ineffable beauty of the endless horizon."

From Latin ineffābilis (“unutterable, unspeakable”), from in- (“not”) + effābilis (“speakable”).