informal <非正式>
no obj.
1- (of an engine in a vehicle) make a roaring sound by being run at very high speed（机动车发动机高速运转时）呜呜叫。
1.1
- with obj. cause (an engine in a vehicle) to make such a sound in this way使（机动车发动机）发呜呜声。
1.2
- no obj., with adverbial of direction(of a vehicle or its driver) travel at great speed（机动车或其司机）高速行驶：
she still had the car and she would vroom up at midnight.
她仍拥有那部车, 会午夜飙车。
- the roaring sound of an engine or motor vehicle（发动机或机动车的）呜呜声。
- used to express or imitate such a sound to suggest speed or acceleration用于模仿这种声音, 表示速度或加速呜：
press the ignition button and vroom!
按点火按钮, 呜的一声加速！
词源
1960s: imitative.