precedent vs topic

precedent and topic both are nouns.

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

As nouns, topic is a hypernym of precedent; that is, topic is a word with a broader meaning than precedent:

Other hypernyms of precedent include subject, theme.

precedent (noun)	topic (noun)
an example that is used to justify similar occurrences at a later time	some situation or event that is thought about
(civil law) a law established by following earlier judicial decisions	the subject matter of a conversation or discussion
a subject mentioned earlier (preceding in time)
a system of jurisprudence based on judicial precedents rather than statutory laws

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