St. Andrew vs Andrew

St. Andrew and Andrew both are nouns.

Word	Noun	Adjective	Verb	Adverb
St. Andrew	Yes	No	No	No
Andrew	Yes	No	No	No

As nouns, St. Andrew and Andrew are synonyms defined as:

St. Andrew and Andrew: (New Testament) disciple of Jesus; brother of Peter; patron saint of Scotland

Other synonyms of St. Andrew include Saint Andrew, Saint Andrew the Apostle.

St. Andrew (noun)	Andrew (noun)
(New Testament) disciple of Jesus; brother of Peter; patron saint of Scotland	(New Testament) disciple of Jesus; brother of Peter; patron saint of Scotland