motivation
英 [ˌməʊtɪˈveɪʃn]   美 [ˌmoʊtɪˈveɪʃn]  
n.
动机;动力;诱因

例句：
Organizations have an interest in ensuring that employee motivation is high. 

各机构皆知获利之道在于确保员工士气高昂。

Money is my motivation 

金钱是我的动力。

Most people said that pay was their main motivation for working. 

大多数人说赚取报酬是他们工作的主要动机。

All research proposals must be accompanied by a full motivation. 

所有研究计划书均须详述研究动机。

He admitted a lack of motivation and a feeling of sloth. 

他承认自己缺乏动力，总想犯懒。