Saint Peter vs St. Peter the Apostle

Saint Peter and St. Peter the Apostle both are nouns.

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

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

Saint Peter and St. Peter the Apostle: 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.

Saint Peter (noun)	St. Peter the Apostle (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