A theologian is a person who studies or is educated in theology. Its root form is the word "theology" which is derived from the Greek: θεολογία, theologia, from θεός, theos or God and λόγος or logos, with the suffix ια, ia, "state of," "property of," "place of"). A literal translation of the Greek word would be "to talk about God" which is what a theologian does.
Theologians use various forms of analysis and argument to help understand, explain, test, critique, defend, or promote any of many religious topics. Theology had its origin in classical Greek thought, but was given new senses within the Christian context as the Fathers of the Church, working within the Hellenistic mould, explained the meaning of the scriptures and Christ's teachings.
Among the many theologians of the Orthodox Church are a number of writers who are remembered as saints with the appellation Theologian: John the Theologian, Gregory the Theologian, and Symeon the New Theologian.