Peter vs St. Peter

Peter and St. Peter both are nouns.

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

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

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 Peter include Saint Peter, Saint Peter the Apostle, Simon Peter, St. Peter the Apostle.

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