motive

n.动机; 原因; 目的adj.发动的; 导致运动的 复数：motives 牛津词典 noun 动机；原因；目的a reason for doing sthThere seemed to be no motive for the murder.这起谋杀案看不出有什么动机。 I'm suspicious of his motives.我怀疑他的动机。 the profit motive (=...