As a Noun: 1. Someone who belongs to the branch of the Christian church which separated from the Catholic church in the sixteenth century. English = Protestant. 2. The set of Christian beliefs that are held by Protestants. English = Protestantism. 3. A person who believes in Jesus Christ and follows his teachings. English = Christian. 4. A religion that is based on the teachings of Jesus Christ and the belief that he was the son of God. English = Christianity. As a Verb or Adjective: 1. To be someone or to relate to someone who belongs to the branch of the Christian church which separated from the Catholic church in the sixteenth century. English = (be) Protestant. 2. To be someone or to relate to someone who believes in Jesus Christ and follows his teachings. English = (be) Christian.