precedent vs preceding

precedent is a noun but preceding is not a noun.

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

precedent (noun)	preceding (noun)
an example that is used to justify similar occurrences at a later time
(civil law) a law established by following earlier judicial decisions
a subject mentioned earlier (preceding in time)
a system of jurisprudence based on judicial precedents rather than statutory laws

precedent (adjective)	preceding (adjective)
preceding in time, order, or significance	existing or coming before
	of a person who has held and relinquished a position or office