Saint Louis vs St. Louis

Saint Louis and St. Louis both are nouns.

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

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

Saint Louis and St. Louis: the largest city in Missouri; a busy river port on the Mississippi River near its confluence with the Missouri River; was an important staging area for wagon trains westward in the 19th century

Other synonyms of Saint Louis include Gateway to the West.

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

Saint Louis and St. Louis: king of France and son of Louis VIII; he led two unsuccessful Crusades; considered an ideal medieval king (1214-1270)

Other synonyms of Saint Louis include Louis IX, Louis IX of France.

Saint Louis (noun)	St. Louis (noun)
the largest city in Missouri; a busy river port on the Mississippi River near its confluence with the Missouri River; was an important staging area for wagon trains westward in the 19th century	the largest city in Missouri; a busy river port on the Mississippi River near its confluence with the Missouri River; was an important staging area for wagon trains westward in the 19th century
king of France and son of Louis VIII; he led two unsuccessful Crusades; considered an ideal medieval king (1214-1270)	king of France and son of Louis VIII; he led two unsuccessful Crusades; considered an ideal medieval king (1214-1270)