precipitancy \pri-SIP-i-tuhn-see, noun:

1. Headlong or rash haste.
2. The quality or state of being precipitant.
3. Precipitancies, hasty or rash acts.

There is one thing I think it my duty to caution you against: the precipitancy with which young men frequently rush into matrimonial engagements, and by their thoughtlessness draw many a deserving woman into scenes of poverty and distress.
— Susanna Rowson, Charlotte Temple

The police authorities have acted in this matter with undue precipitancy.
— Joseph Smith Fletcher, Green Ink and Other Stories

Precipitancy comes from the Latin word praecipitāre meaning “to cast down headlong.”