likely to do something suddenly, without considering the results of your actions

He's so impetuous - why can't he think things over before he rushes into them? 他太冲动了——为什么他急着做事前不能仔细考虑一下呢？

said or done suddenly, without considering the likely results

The governor may now be regretting her impetuous promise to reduce unemployment by half. 州长现在可能后悔她轻率地许诺要将失业人数减少一半。