President Kennedy vs Jack Kennedy

President Kennedy and Jack Kennedy both are nouns.

Word	Noun	Adjective	Verb	Adverb
President Kennedy	Yes	No	No	No
Jack Kennedy	Yes	No	No	No

As nouns, President Kennedy and Jack Kennedy are synonyms defined as:

President Kennedy and Jack Kennedy: 35th President of the United States; established the Peace Corps; assassinated in Dallas (1917-1963)

Other synonyms of President Kennedy include JFK, John Fitzgerald Kennedy, Kennedy, President John F. Kennedy.

President Kennedy (noun)	Jack Kennedy (noun)
35th President of the United States; established the Peace Corps; assassinated in Dallas (1917-1963)	35th President of the United States; established the Peace Corps; assassinated in Dallas (1917-1963)