precedent vs precedency

precedent and precedency both are nouns.

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

precedent (noun)	precedency (noun)
an example that is used to justify similar occurrences at a later time	the act of preceding in time or order or rank (as in a ceremony)
(civil law) a law established by following earlier judicial decisions	preceding in time
a subject mentioned earlier (preceding in time)	status established in order of importance or urgency
a system of jurisprudence based on judicial precedents rather than statutory laws

precedent (adjective)	precedency (adjective)
preceding in time, order, or significance