Saint Vincent and the Grenadines vs St. Vincent and the Grenadines

Saint Vincent and the Grenadines and St. Vincent and the Grenadines both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Vincent and the Grenadines	Yes	No	No	No
St. Vincent and the Grenadines	Yes	No	No	No

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

Saint Vincent and the Grenadines and St. Vincent and the Grenadines: an island country in the central Windward Islands; achieved independence from the United Kingdom in 1979

Saint Vincent and the Grenadines (noun)	St. Vincent and the Grenadines (noun)
an island country in the central Windward Islands; achieved independence from the United Kingdom in 1979	an island country in the central Windward Islands; achieved independence from the United Kingdom in 1979