precipitant

adj

1. Inclined to make rapid decisions without due consideration; hasty, impulsive, rash.

   “[T]heſe dreams the præcipitant and unskilfull are forvvard to conceit to be Repreſentations extraordinary and ſupernatural, vvhich they call Revelations or Viſions, of vvhich there can be no certainty at all no more then of a Dream.”

   “She had good Qualities—is generous—noble—but has ſtrong Paſſions, and is thoughtleſs and precipitant.”

2. Of a fall: straight downwards; headlong.

   “[W]ithout further pauſe / Down right into the Worlds firſt Region throws / His flight precipitant, and windes with eaſe / Through the pure marble Air his oblique way / Amongſt innumerable Starrs, […]”

   “[H]eedleſs vvhile they [the birds] ſtrain / Their tuneful Throats, the tovv'ring, heavy Lead [i.e., bullets] / O'er-takes their Speed; they leave their little Lives / Above the clouds, præcipitant to Earth.”

3. (figuratively)Acting, happening, or moving quickly; fast, rapid, swift; also, abrupt, sudden, unexpected.

   “[W]ere the Aer copiouſly mixed vvith the Sap here, as in the Pith, Fruit, and other Parenchymous Parts; it vvould give ſo quick a Ferment to the Sap, as to dilate and amplify the Bladders of the Seed, beyond its preſent compact and durable Texture; and ſo expoſe it, either to a precipitant Grovvth, or ſudden Rot.”

   “Shou'd he return, that troop ſo blithe and bold, / VVith purple robes invvrought, and ſtiff vvith gold, / Precipitant in fear, vvou'd vving their flight, / And curſe their cumbrous pride's unvvieldy vveight.”

4. That causes precipitation (“formation of a heavier solid in a lighter liquid as a result of a chemical reaction”).

adv

1. (archaic)Synonym of precipitantly (“in a precipitant or headlong manner; with foolish or rash haste”).

   “The Hoary Froſts, and Northern Blaſts take care / Thy muddy Bev'rage to ſerene, and drive / Præcipitant the baſer, ropy Lees.”

noun

1. Something which causes or hastens the occurrence of an act or event; specifically (chiefly psychology), something which brings about a mental or physiological condition.
2. A substance that, when added to a solution, causes a dissolved substance to form a precipitate.

   “[B]y putting ſome of the arſenical liquor into a ſtrong ſolution of common ſublimate made in fair vvater […] vve had a copious precipitate, ſuch as might have been expected from an alcaline precipitant; […]”