"falling headlong, rushing hastily downward," 1610s, from Latin praecipitantem, present participle of praecipitare "to throw or dive headlong; be hasty" (see precipitate (v.)). Meaning "rashly hasty" is from 1640s. As a noun in chemistry, "an agent which when added to a solution separates something dissolved and causes it to precipitate or fall to the bottom," from 1680s. The adjective senses now are taken by precipitate (adj.). Related: Precipitance.
updated on October 13, 2020