blasphemy, in religion, words or actions that display irreverence toward or contempt for God or that which is held sacred. Blasphemy is regarded as an offense against the community to varying degrees, depending on the extent of the identification of a religion with the society at large or the government. Sedition, an attack on the sovereign, is thus analogous; both it and blasphemy can be seen as subversive of order and authority. Heresy, on the other hand, is a matter of competing claims for doctrinal correctness; the dominant (orthodox) faction, however, often defines the heretic as blasphemous.
Blasphemy has been a crime in many religions and cultures, wherever there is something sacred to protect. Socrates was prosecuted for blasphemy, and Mosaic law prescribed death for cursing the name of God. Jesus was tried for blasphemy, while Christians regarded the action of the Jews in trying him as itself blasphemous.
Secular modern states often retain blasphemy laws, but they are infrequently enforced. In the United States, state blasphemy laws remain on the books, but the Supreme Court's expansive interpretation of the First Amendment to the U.S. Constitution makes it likely that any blasphemy prosecution would now be regarded as an impermissible establishment of religion. In countries governed under Islamic law, the concept of blasphemy is broad, embracing many kinds of disrespect or denial of religion; the condemnation (1988) of the author Salman Rushdie by Iranian clerics is a recent example of theocratic action.