mysterium tremendum
/mɪˌstɪərɪəm trɪˈmɛndəm/noun
A great or profound mystery, especially the mystery of God or of existence; the overwhelming awe felt by a person contemplating such a mystery.
- In theological contexts the term is associated particularly with the German Protestant theologian Rudolf Otto (1869–1937)..
Origin
Mid 19th century. From post-classical Latin mysterium tremendum tremendous mystery from classical Latin mystērium + tremendum, neuter of tremendus.