Her impulsive decision to quit her job and travel the world surprised everyone.

impulsive 是形容词，由动词 impulse（冲动）加上后缀 -ive 构成，表示"冲动的、易冲动的"。impulse 来自拉丁语，原意是"推动、驱使"，引申为"突然的冲动"。 impulsive decision 指"未经深思熟虑、一时冲动做出的决定"。