biology vs hoary

biology is a noun but hoary is not a noun.

Word	Noun	Adjective	Verb	Adverb
biology	Yes	No	No	No
hoary	No	Yes	No	No

biology (noun)	hoary (noun)
the science that studies living organisms
all the plant and animal life of a particular region
characteristic life processes and phenomena of living organisms

biology (adjective)	hoary (adjective)
	covered with fine whitish hairs or down
	ancient
	showing characteristics of age, especially having grey or white hair