precipitate

Many people, including usage commentators, are insistent about keeping the adjectives "precipitate" and "precipitous" distinct. "Precipitate," they say, means "headlong" or "impetuous"; "precipitous" means only "steep." And, indeed, "precipitate" is used mostly in the "headlong" sense, whereas "precipitous" usually means "steep." But one shouldn't be too hasty about insisting on the distinction. The truth is that "precipitate" and "precipitous" have had a tendency to overlap for centuries. Lexicographer Samuel Johnson, in his dictionary of 1755, defined "precipitate" as "steeply falling," "headlong," and "hasty," while "precipitous" was "headlong; steep," and "hasty." Noah Webster's 1828 dictionary included much the same definitions. The words' etymologies overlap as well. Both ultimately come from Latin praeceps, which means "headlong."