McKinley vs William McKinley

McKinley and William McKinley both are nouns.

Word	Noun	Adjective	Verb	Adverb
McKinley	Yes	No	No	No
William McKinley	Yes	No	No	No

As nouns, McKinley and William McKinley are synonyms defined as:

McKinley and William McKinley: 25th President of the United States; was assassinated by an anarchist (1843-1901)

Other synonyms of McKinley include President McKinley.

McKinley (noun)	William McKinley (noun)
a mountain in south central Alaska; the highest peak in North America (20,300 feet high)	25th President of the United States; was assassinated by an anarchist (1843-1901)
25th President of the United States; was assassinated by an anarchist (1843-1901)