The correct pronunciation of "Cathar" is "Sah-thair".
It is a Hebrew word meaning, "hidden", and "secret".
סתר Strong's Hebrew 5641
אשר־דרכו נסתרה "Asher Darko ni Setharah" Asher is a Hidden Path (Job 3:23)

The name of God associated with Cathar is Ehyeh Asher Ehyeh (Hebrew: אהיה אשר אהיה).

Exodus 3:6 "Moreover he said, I am the God of thy father, the God of Abraham, the God of Isaac, and the God of Jacob. And Moses hid (waya-cathar) his face; for he was afraid to look upon God."

"Cathar" is also spelled: סתור "Sah-thoor". (Gematria 666)
Numbers 13:13: "Of the tribe of Asher, Cathar (Sethur) the son of Michael.