King vs Billie Jean King

King and Billie Jean King both are nouns.

Word	Noun	Adjective	Verb	Adverb
King	Yes	No	No	No
Billie Jean King	Yes	No	No	No

As nouns, King and Billie Jean King are synonyms defined as:

King and Billie Jean King: United States woman tennis player (born in 1943)

Other synonyms of King include Billie Jean Moffitt King.

King (noun)	Billie Jean King (noun)
United States charismatic civil rights leader and Baptist minister who campaigned against the segregation of Blacks (1929-1968)	United States woman tennis player (born in 1943)
United States guitar player and singer of the blues (born in 1925)
United States woman tennis player (born in 1943)