anteriority vs antecedency

anteriority and antecedency both are nouns.

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

As nouns, anteriority and antecedency are synonyms defined as:

Other synonyms of anteriority include antecedence, precedence, precedency, priority.

anteriority (noun)	antecedency (noun)
the quality of being in front or (in lower animals) toward the head	preceding in time
preceding in time