The Greek adjective apokryphos (G614) means hidden, secret, or stored away. It is the adjectival form of apokrypto (G613, to hide). The word appears three times in the New Testament: Mark 4:22; Luke 8:17; and Colossians 2:3. In extrabiblical literature, it came to describe texts considered too sacred or esoteric for general distribution — hence the English word 'apocryphal.'
Colossians 2:3 is the most theologically rich use of apokryphos: Paul writes that in Christ 'are hidden (apokryphoi) all the treasures of wisdom and knowledge.' This is a direct counter to the Colossian false teachers who claimed access to secret wisdom beyond what Christ offered. Paul's answer: Christ is not one among many paths to hidden wisdom — He is the hidden wisdom, now revealed. All the treasures of divine knowledge are not scattered among various traditions and teachings; they are concentrated and stored up (apokryphoi) in Jesus Christ. To know Him is to have access to everything God has to say.