A preacher is a person who delivers sermons or homilies on religious topics to an assembly of people. Less common are preachers who preach on the street, or those whose message is not necessarily religious, but who preach components such as a moral or social worldview or philosophy.

Jesus was an itinerant apocalyptic preacher in 1st-century Judea.
Street preacher in Praça da Sé, São Paulo, Brasil