Saint Olav vs St. Olaf

Saint Olav and St. Olaf both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Olav	Yes	No	No	No
St. Olaf	Yes	No	No	No

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

Other synonyms of Saint Olav include Olaf II, Olaf II of Norway, Olav II, Saint Olaf, St. Olav.

Saint Olav (noun)	St. Olaf (noun)
King and patron saint of Norway (995-1030)	King and patron saint of Norway (995-1030)