Plastos (πλαστός) means molded, fabricated, feigned, or counterfeit. Derived from plasso (G4111, to mold or form), it describes something that has been artificially shaped or manufactured — and by extension, something that is false or made-up. In its sole NT occurrence, it refers to fabricated words or stories invented to exploit believers.
Peter uses plastos in 2 Peter 2:3 to describe the tactics of false teachers: "In their greed these teachers will exploit you with fabricated stories" (plastois logois). The word choice is devastating — these teachers are spiritual counterfeiters. They mold and shape persuasive-sounding doctrines not from divine revelation but from human invention, specifically to exploit people financially and spiritually. The English word "plastic" derives from this root, carrying the same sense of something artificially molded. Peter's warning is timeless: not every compelling-sounding teaching originates from God. Believers must test all teaching against Scripture (Acts 17:11) because false teachers specialize in crafting plausible-sounding but ultimately plastos — fabricated — doctrine.