Saint Patrick vs St. Patrick

Saint Patrick and St. Patrick both are nouns.

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

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

Saint Patrick and St. Patrick: Apostle and patron saint of Ireland; an English missionary to Ireland in the 5th century

Other synonyms of Saint Patrick include Patrick.

Saint Patrick (noun)	St. Patrick (noun)
Apostle and patron saint of Ireland; an English missionary to Ireland in the 5th century	Apostle and patron saint of Ireland; an English missionary to Ireland in the 5th century