good old boy vs Southerner

good old boy and Southerner both are nouns.

Word	Noun	Adjective	Verb	Adverb
good old boy	Yes	No	No	No
Southerner	Yes	No	No	No

As nouns, Southerner is a hypernym of good old boy; that is, Southerner is a word with a broader meaning than good old boy:

good old boy: a white male Southerner with an unpretentious convivial manner and conservative or intolerant attitudes and a strong sense of fellowship with and loyalty to other members of his peer group
Southerner: an American who lives in the South

Other hypernyms of good old boy include white man.

good old boy (noun)	Southerner (noun)
a white male Southerner with an unpretentious convivial manner and conservative or intolerant attitudes and a strong sense of fellowship with and loyalty to other members of his peer group	an American who lives in the South