impulse

1. N-VAR An impulse is a sudden desire to do something. 冲动

Unable to resist the impulse, he glanced at the sea again. 他抑制不住冲动，又看了一眼大海。

2. N-COUNT An impulse is a short electrical signal that is sent along a wire or nerve or through the air, usually as one of a series. 脉冲

It works by sending a series of electrical impulses which are picked up by hi-tech sensors. 它通过传输由高技术传感器收集的电脉冲而起作用。

3. ADJ An impulse buy or impulse purchase is something that you decide to buy when you see it, although you had not planned to buy it. 一时心血来潮的[ADJ n]

The curtains were an impulse buy. 这窗帘是一时心血来潮买下的。

4. PHRASE If you do something on impulse, you suddenly decide to do it, without planning it. 凭一时冲动

Sean's a fast thinker, and he acts on impulse. 肖恩是个思维敏捷、凭一时冲动行事的人。