- an amendment to the U.S. Constitution, ratified in 1791 as part of the Bill of Rights, prohibiting Congress from interfering with freedom of religion, speech, assembly, or petition.
An amendment to the United States Constitution guaranteeing the rights of free expression and action that are fundamental to democratic government. These rights include freedom of assembly, freedom of the press, freedom of religion, and freedom of speech. The government is empowered, however, to restrict these freedoms if expression threatens to be destructive. Argument over the extent of First Amendment freedoms has often reached the Supreme Court. (See clear and present danger, libel, and obscenity.)