stratagem       
noun [ C or U ] uk/ˈstræt.ə.dʒəm/ us/ˈstræt̬.ə.dʒəm/
 策略;计策,计谋
a carefully planned way of achieving or dealing with something, often involving a trick
  Her stratagem for dealing with her husband's infidelities was to ignore them. 她对待丈夫不忠的策略就是佯装不知。 
 He was a master of stratagem. 他很有谋略。