precipitousness vs precipitancy

precipitousness and precipitancy both are nouns.

Word	Noun	Adjective	Verb	Adverb
precipitousness	Yes	No	No	No
precipitancy	Yes	No	No	No

As nouns, precipitousness and precipitancy are synonyms defined as:

precipitousness and precipitancy: the quality of happening with headlong haste or without warning

Other synonyms of precipitousness include abruptness, precipitance, precipitateness, suddenness.

precipitousness (noun)	precipitancy (noun)
the property possessed by a slope that is very steep	the quality of happening with headlong haste or without warning
the quality of happening with headlong haste or without warning