Jack Kennedy vs JFK

Jack Kennedy and JFK both are nouns.

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

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

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

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

Jack Kennedy (noun)	JFK (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)