biology vs acephalous

biology is a noun but acephalous is not a noun.

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

biology (noun)	acephalous (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)	acephalous (adjective)
	lacking a head or a clearly defined head