Polk vs President Polk

Polk and President Polk both are nouns.

Word	Noun	Adjective	Verb	Adverb
Polk	Yes	No	No	No
President Polk	Yes	No	No	No

As nouns, Polk and President Polk are synonyms defined as:

Polk and President Polk: 11th President of the United States; his expansionism led to the Mexican War and the annexation of California and much of the southwest (1795-1849)

Other synonyms of Polk include James K. Polk, James Knox Polk, James Polk.

Polk (noun)	President Polk (noun)
11th President of the United States; his expansionism led to the Mexican War and the annexation of California and much of the southwest (1795-1849)	11th President of the United States; his expansionism led to the Mexican War and the annexation of California and much of the southwest (1795-1849)