antecedency vs antecedent

antecedency and antecedent both are nouns.

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

antecedency (noun)	antecedent (noun)
preceding in time	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

antecedency (adjective)	antecedent (adjective)
	preceding in time or order