instancy vs rapidity

instancy and rapidity both are nouns.

Word	Noun	Adjective	Verb	Adverb
instancy	Yes	No	No	No
rapidity	Yes	No	No	No

As nouns, rapidity is a hypernym of instancy; that is, rapidity is a word with a broader meaning than instancy:

Other hypernyms of instancy include celerity, quickness, rapidness, speediness.

instancy (noun)	rapidity (noun)
the quality of being insistent	a rate that is rapid
the quickness of action or occurrence