The Greek adjective adolos (ἄδολος) means without deceit, pure, unadulterated, or sincere. It is the alpha-privative form of dolos (deceit, bait, craftiness). It appears only once in the New Testament — 1 Peter 2:2 — where Peter commands new believers to "crave pure spiritual milk" (to logikon adolon gala) — the unadulterated, undiluted Word of God, so that they may grow up in their salvation.
Peter's metaphor of adolos milk is both simple and profound. Just as a nursing infant needs pure (adolos) milk — not watered down, not mixed with anything harmful — so new believers (and all believers) need the pure, undiluted Word of God. The word adolos (without deceit) stands against any corruption, adulteration, or dilution of God's truth. In an age of felt-need preaching, therapeutic Christianity, and biblical truth softened for cultural comfort, adolos is the standard: give people the real thing. Peter's command stands against the "doctrines of demons" (1 Timothy 4:1) and the "another gospel" Paul warns against (Galatians 1:8). The adolos Word is both milk for infants and the sword of the Spirit (Hebrews 4:12) — the same truth at different stages of digestion. It is always pure; it is never watered down.