St. Nicholas vs Saint Nicholas

St. Nicholas and Saint Nicholas both are nouns.

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

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

St. Nicholas and Saint Nicholas: a bishop in Asia Minor who is associated with Santa Claus (4th century)

Other synonyms of St. Nicholas include Nicholas.

St. Nicholas (noun)	Saint Nicholas (noun)
a bishop in Asia Minor who is associated with Santa Claus (4th century)	a bishop in Asia Minor who is associated with Santa Claus (4th century)
	the legendary patron saint of children; an imaginary being who is thought to bring presents to children at Christmas