Old Testament vs Esther

Old Testament and Esther both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old Testament	Yes	No	No	No
Esther	Yes	No	No	No

Old Testament (noun)	Esther (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 telling of a beautiful Jewess who became queen of Persia and saved her people from massacre
	(Old Testament) a beautiful Jewess chosen by the king of Persia to be his queen; she stopped a plot to massacre all the Jews in Persia (an event celebrated by Jews as the feast of Purim)