Pre-Covid Era

According to Contactee Richard Miller, translates literally as “Farewell, good brothers.”

Miller was known for several radio programs including “Space Tapes”, “Galaxy” and “Solar Cross.” In these programs, he would channel beings via Tensor Beam, who educated the listeners on ancient history, space brother technology, and what it was like to live on Mars.

Each of these channeling sessions ended with the entity on the other end of the line saying “Adonai” or “Adonai vasu baragas.” This phrase took on life beyond Mr. Miller, and soon other contactees were using it as well. ~ Source

It is a cross between:
Hebrew — אדוני Boragus Vasu (In Hebrew Adonai is the plural of Adon, meaning “Lord, Lord, LORD, master, or owner” )
and is also Hindu — Adonai वासु Boragus ~ Source

In German, Adonai, in Ashkenazic pronunciation Adaunoi, Adoinoi, Adonoi, is one of the descriptions for YHWH, God’s proper name in Tanach, the Jewish Bible.