The precise definition of Western esotericism has been debated by various academics, with a number of different options proposed. One scholarly model adopts its definition of "esotericism" from certain esotericist schools of thought themselves, treating "esotericism" as a perennialist hidden, inner tradition. A second perspective argues that it is a category that encompasses world views which seek to embrace an 'enchanted' world view in the face of increasing de-enchantment. A third view, propounded by Wouter Hanegraaff, views Western esotericism as a category encompassing all of Western culture's "rejected knowledge" that is accepted by neither the scientific establishment nor orthodox religious authorities.

The earliest traditions to later be labelled as forms of Western esotericism emerged in the Eastern Mediterranean during Late Antiquity, where Hermetism, Gnosticism, and Neoplatonism developed as schools of thought distinct from mainstream Christianity. . . . more

https://en.wikipedia.org/wiki/Western_esotericism