Saint Peter vs St. Peter

Saint Peter and St. Peter both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Peter	Yes	No	No	No
St. Peter	Yes	No	No	No

As nouns, Saint Peter and St. Peter are synonyms defined as:

Saint Peter and St. Peter: disciple of Jesus and leader of the Apostles; regarded by Catholics as the vicar of Christ on earth and first Pope

Other synonyms of Saint Peter include Peter, Saint Peter the Apostle, Simon Peter, St. Peter the Apostle.

Saint Peter (noun)	St. Peter (noun)
disciple of Jesus and leader of the Apostles; regarded by Catholics as the vicar of Christ on earth and first Pope	disciple of Jesus and leader of the Apostles; regarded by Catholics as the vicar of Christ on earth and first Pope