posterior vs excrement

posterior and excrement both are nouns.

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

posterior (noun)	excrement (noun)
the fleshy part of the human body that you sit on	waste matter (as urine or sweat but especially feces) discharged from the body
a tooth situated at the back of the mouth

posterior (adjective)	excrement (adjective)
located at or near or behind a part or near the end of a structure
coming at a subsequent time or stage