Yiddish vs High German

Yiddish and High German both are nouns.

Word	Noun	Adjective	Verb	Adverb
Yiddish	Yes	No	No	No
High German	Yes	No	No	No

As nouns, High German is a hypernym of Yiddish; that is, High German is a word with a broader meaning than Yiddish:

Yiddish: a dialect of High German including some Hebrew and other words; spoken in Europe as a vernacular by many Jews; written in the Hebrew script
High German: the standard German language; developed historically from West Germanic

Other hypernyms of Yiddish include German, German language, High German language.

Yiddish (noun)	High German (noun)
a dialect of High German including some Hebrew and other words; spoken in Europe as a vernacular by many Jews; written in the Hebrew script	the standard German language; developed historically from West Germanic