Saint Kitts vs St. Christopher

Saint Kitts and St. Christopher both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Kitts	Yes	No	No	No
St. Christopher	Yes	No	No	No

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

Saint Kitts and St. Christopher: the largest of the islands comprising Saint Christopher-Nevis

Other synonyms of Saint Kitts include Saint Christopher, St. Kitts.

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