/'ɪmpʌls; `ɪmpʌls/
n
1 (a) [C] ~ (to do sth) sudden urge to act without thinking about the results 凭冲动行事（未顾及後果）; 突如其来的念头
*He felt an irresistible impulse to jump. 他突然有个无法抗拒的冲动, 想跳下去.
* check/curb/resist an impulse 抑制[约束/遏止]冲动.
(b) [U] tendency to act in this way 好冲动行事
*a man of impulse 易冲动的人.
2 [C] push or thrust; stimulus; impetus 推动; 冲力; 刺激; 推动力
*give an impulse to industrial expansion 促进工业的扩展.
3 [C] stimulating force in a nerve or an electric circuit that causes a reaction 神经冲动; 电路脉冲
*nerve impulses神经冲动.
4 (idm 习语) on impulse suddenly and without previous thinking or planning 一时冲动
*On impulse, I picked up the phone and rang my sister in Australia. 我一时心血来潮, 拿起话筒就给在澳大利亚的妹妹打了个电话.

n
[Date: 1600-1700; Language: Latin;Origin: impulsus, from the past participle of impellere; IMPEL]
[U and C]
a sudden strong desire to do something without thinking about whether it is a sensible thing to do
= urgeimpulse to do sth
　a sudden impulse to laugh
　Marge's first impulse was to run.
　Gerry couldn't resist the impulse to kiss her.
on impulse
　On impulse, I picked up the phone and rang her.
　Most beginners buy plants on impulse and then hope for the best.
impulse buying/shopping
(=when you buy things that you had not planned to buy)
[C]technical
a short electrical signal that travels in one direction along a nerve or wire
　The eye converts light signals to nerve impulses.
[C]
a reason or aim that causes a particular kind of activity or behaviour
　It is the passions which provide the main impulse of music.