Precipitately describes doing something too fast and without enough thought — rushing into it, acting before you have looked. If a government acts precipitately, it moves before it understands the situation, and the word tells you the writer thinks that was a mistake. It also has a plainer, more physical use: leaving or falling suddenly and steeply. 'He left precipitately' means he rushed out, often as if something had frightened him; share prices can fall precipitately. The picture inside the word is of something thrown headfirst off a cliff, which is exactly what the Latin says. This is a formal, written adverb — journalism, history books, official reports. In speech people say 'too quickly', 'in a rush', 'without thinking'. Two neighbours are worth keeping straight. 'Precipitously' is the one people mostly use for steep falls in numbers, and the two words have been blurring together for a long time, so you will see both. 'Precipitantly' is rarer still. Learners do not need to produce this word; you need to recognise it and hear the criticism in it, because it is almost never neutral.

倉促地、貿然地(帶批評語氣：沒想清楚就衝下去做);也可指「陡然、急遽地」下跌或離開。書面語。