"No word in our language — not even "Socialism"— has been employed more loosely than "Mysticism." … The history of the word begins in close connexion with the Greek mysteries. A mystic is one who has been, or is being, initiated into some esoteric knowledge of Divine things, about which he must keep his mouth shut…"
January 1, 1970
https://en.wikiquote.org/wiki/William_Ralph_Inge