antecedence vs precedency

antecedence and precedency both are nouns.

Word	Noun	Adjective	Verb	Adverb
antecedence	Yes	No	No	No
precedency	Yes	No	No	No

As nouns, antecedence and precedency are synonyms defined as:

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

antecedence (noun)	precedency (noun)
preceding in time	the act of preceding in time or order or rank (as in a ceremony)
	preceding in time
	status established in order of importance or urgency