If something is blasphemous, it is insulting to God or to people’s religious beliefs — a sentence, a joke, a picture, a song, a book, even a way of using a holy name. The word describes the thing said or done, not only the person. It is a serious adjective and feels rather formal. You meet it in news about religion, in fights about art, and in warnings from faith leaders. Though actually, people stretch it: one group calls a film blasphemous, another calls the same film only bold. The word always carries someone else’s hurt or anger about what is holy.