straight person vs somebody

straight person and somebody both are nouns.

Word	Noun	Adjective	Verb	Adverb
straight person	Yes	No	No	No
somebody	Yes	No	No	No

As nouns, somebody is a hypernym of straight person; that is, somebody is a word with a broader meaning than straight person:

straight person: a person having a sexual orientation to persons of the opposite sex
somebody: a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential

Other hypernyms of straight person include individual, mortal, person, someone, soul.

straight person (noun)	somebody (noun)
a person having a sexual orientation to persons of the opposite sex	a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential