anterior vs antecedent

anterior and antecedent both are nouns.

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

anterior (noun)	antecedent (noun)
a tooth situated at the front of the mouth	the referent of an anaphor; a phrase or clause that is referred to by an anaphoric pronoun
	a preceding occurrence or cause or event
	someone from whom you are descended (but usually more remote than a grandparent)
	anything that precedes something similar in time

anterior (adjective)	antecedent (adjective)
of or near the head end or toward the front plane of a body	preceding in time or order
earlier in time