Samuel Johnson vs Johnson

Samuel Johnson and Johnson both are nouns.

Word	Noun	Adjective	Verb	Adverb
Samuel Johnson	Yes	No	No	No
Johnson	Yes	No	No	No

As nouns, Samuel Johnson and Johnson are synonyms defined as:

Samuel Johnson and Johnson: English writer and lexicographer (1709-1784)

Other synonyms of Samuel Johnson include Dr. Johnson.

Samuel Johnson (noun)	Johnson (noun)
English writer and lexicographer (1709-1784)	17th President of the United States; was elected vice president and succeeded Lincoln when Lincoln was assassinated; was impeached but acquitted by one vote (1808-1875)
	36th President of the United States; was elected vice president and succeeded Kennedy when Kennedy was assassinated (1908-1973)
	English writer and lexicographer (1709-1784)