Old Testament vs Book of Proverbs

Old Testament and Book of Proverbs both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old Testament	Yes	No	No	No
Book of Proverbs	Yes	No	No	No

Old Testament (noun)	Book of Proverbs (noun)
the collection of books comprising the sacred scripture of the Hebrews and recording their history as the chosen people; the first half of the Christian Bible	an Old Testament book consisting of proverbs from various Israeli sages (including Solomon)