The adjective θρησκος (threshkos) appears to pertain to the formal, cultic or ritualistic aspect of religion. It's unclear where this word comes from, and thus what it precisely means, but the formidable Belgian linguist Emile Boisacq (Dictionnaire étymologique de la langue grecque, 1907-1916), proposed relations with the familiar noun θεραπων (therapon), care-taker or fire-provider, which in turn probably has to do with θερω (thero), to heat or keep warm.

Contrary to popular belief, the Bible is not about religion and all about information technology (see our articles on the names YHWH and Logos), but as every schoolchild will confirm, learning how to read and write comes from repeating the same exercises over and over. Particularly to an illiterate audience that does not comprehend text — that is an audience that regards the resurrection of someone else's, even a dead person's, sayings from incantations of esoteric symbols to be an act of supernatural magic — the endless repetition of exercises may appear to invoke powerful spirits and energies. But to anyone who understands why students perform rituals (namely to develop the mental equivalent of muscle memory), the endless repetition of rituals without the hope of actually achieving some useful skill is utter nonsense.

Our adjective θρησκος (threshkos) occurs in the New Testament in James 1:26 only, but from it derives: