- [countable]
a strong desire to do something 冲动；强烈欲望 - [uncountable]
a reason for doing something 理由；缘由
Word Originlate Middle English (in the sense ‘the action or an instance of impelling’): via Old French from Latin impulsio(n-), from the verb impellere, from in- ‘towards’ + pellere ‘to drive’.