Saint Vincent vs St. Vincent

Saint Vincent and St. Vincent both are nouns.

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

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

Saint Vincent and St. Vincent: an island in the center of the Windward Islands; the largest of the islands comprising Saint Vincent and the Grenadines

Saint Vincent (noun)	St. Vincent (noun)
an island in the center of the Windward Islands; the largest of the islands comprising Saint Vincent and the Grenadines	an island in the center of the Windward Islands; the largest of the islands comprising Saint Vincent and the Grenadines