Definition of "precipitance"

I gasped, at this frightful precipitance—I was going to open with warmth against it.

1748, [Samuel Richardson], “Letter XX”, in Clarissa. Or, The History of a Young Lady: […], volumes (please specify |volume=I to VII), London: […] S[amuel] Richardson; […]

We have been hurried on by our feelings to a degree of Precipitance which ill accords with the claims of our Friends, or the opinion of the World.

c. 1794, Jane Austen, Lady Susan