Saint Christopher vs Christopher

Saint Christopher and Christopher both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Christopher	Yes	No	No	No
Christopher	Yes	No	No	No

As nouns, Saint Christopher and Christopher are synonyms defined as:

Saint Christopher and Christopher: Christian martyr and patron saint of travellers (3rd century)

Other synonyms of Saint Christopher include St. Christopher.

Saint Christopher (noun)	Christopher (noun)
the largest of the islands comprising Saint Christopher-Nevis	Christian martyr and patron saint of travellers (3rd century)
Christian martyr and patron saint of travellers (3rd century)