adj. Steep, like a precipice; as, a precipitous cliff or mountain. adj. Headlong; as, precipitous fall. adj. Hasty; rash; quick; sudden; precipitate; as, precipitous attempts. from the GNU version of the Collaborative International Dictionary of English. adj. Steep, like a precipice. adj. Headlong. adj. Hasty; rash; quick; sudden; precipitate.