Reuben vs Old Testament

Reuben and Old Testament both are nouns.

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

Reuben (noun)	Old Testament (noun)
a hot sandwich with corned beef (or pastrami), Swiss cheese and sauerkraut on rye bread	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
(Old Testment) a son of Jacob and forefather of one of the tribes of Israel