impulse

Universal Words noun 1 [C,usually sing,U] ~ (to do sth) a sudden strong wish or need to do sth, without stopping to think about the results: He had a sudden impulse to stand up and sing. * I resisted the impulse to laugh. * Her first impulse was to run away. * The door was open and on (an) impulse she went inside. * He tends to act on impulse. 2 [C] (technical) a force or movement of energy that causes sth else to react: nerve / electrical impulses * The impulse is conducted along the length of the wire. 3 [C,usually sing,U] (formal) something that causes sb/sth to do sth or to develop and make progress: to give an impulse to the struggling car industry * He was motivated by the impulse for social reform.