caudal vs posterior

caudal is not a noun while posterior is a noun.

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

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

caudal (adjective)	posterior (adjective)
constituting or relating to a tail	located at or near or behind a part or near the end of a structure
resembling a tail	coming at a subsequent time or stage
situated in or directed toward the part of the body from which the tail arises

caudal (adverb)	posterior (adverb)
toward the posterior end of the body