gospel vs doo-wop

gospel and doo-wop both are nouns.

Word	Noun	Adjective	Verb	Adverb
gospel	Yes	No	No	No
doo-wop	Yes	No	No	No

As nouns, doo-wop is a hyponym of gospel; that is, doo-wop is a word with a more specific, narrower meaning than gospel:

gospel: folk music consisting of a genre of a cappella music originating with Black slaves in the United States and featuring call and response; influential on the development of other genres of popular music (especially soul)
doo-wop: a genre (usually a cappella) of Black vocal-harmony music of the 1950s that evolved in New York City from gospel singing; characterized by close four-part harmonies; the name derived from some of the nonsense syllables sung by the backup

Other hyponyms of gospel include soul.

gospel (noun)	doo-wop (noun)
a doctrine that is believed to be of great importance	a genre (usually a cappella) of Black vocal-harmony music of the 1950s that evolved in New York City from gospel singing; characterized by close four-part harmonies; the name derived from some of the nonsense syllables sung by the backup
the written body of teachings of a religious group that are generally accepted by that group
an unquestionable truth
folk music consisting of a genre of a cappella music originating with Black slaves in the United States and featuring call and response; influential on the development of other genres of popular music (especially soul)