posterior vs anterior

posterior and anterior both are nouns.

Word	Noun	Adjective	Verb	Adverb
posterior	Yes	Yes	No	No
anterior	Yes	Yes	No	No

posterior (noun)	anterior (noun)
the fleshy part of the human body that you sit on	a tooth situated at the front of the mouth
a tooth situated at the back of the mouth

posterior (adjective)	anterior (adjective)
located at or near or behind a part or near the end of a structure	of or near the head end or toward the front plane of a body
coming at a subsequent time or stage	earlier in time