This adjective describes what is unlawful or contrary to proper law—particularly divine or moral law. In Acts 10:28, Peter explains to Cornelius that it is 'unlawful' for a Jew to associate with Gentiles—though Peter has learned God has cleansed all peoples. In 1 Peter 4:3, it describes the 'illicit' idolatries Gentiles practiced in their former pagan life. The word emphasizes violation of law or custom, behavior that transgresses established boundaries. It carries moral weight, marking conduct as improper, forbidden, outside the bounds of what is lawful and right.