Meaning

noun a religion based on mystical communion with an ultimate reality

noun obscure or irrational thought

originFrom mystic + -ism, from Old French mistique (“mysterious, full of mystery”), from Latin mysticus (“mystical, mystic, of secret rites”), from Ancient Greek μυστικός (mustikós, “secret, mystic”), from μύστης (mústēs, “one who has been initiated, initiate”) from μῡ́ω (mū́ō, “to close one's lips or eyes; initiate into the mysteries”). Compare Asturian misticismu, Catalan misticisme, French…

Etymology from Wiktionary, CC BY-SA 3.0