importunity vs instancy

importunity and instancy both are nouns.

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

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

importunity: Quality of a person who is given to making importunate demands, being greedily or thoughtlessly demanding.
instancy: the quality of being insistent

Other hypernyms of importunity include imperativeness.

importunity (noun)	instancy (noun)
Quality of a person who is given to making importunate demands, being greedily or thoughtlessly demanding.	the quality of being insistent
insistent solicitation and entreaty	the quickness of action or occurrence