smokescreen

名词 smokescreen:

1. (military) screen consisting of a cloud of smoke that obscures movements
   同义词：smoke screen
2. an action intended to conceal or confuse or obscure
   同义词：smoke screen

1. The export business is just a smokescreen for his activity as a spy.
   他做出口生意只是为他的间谍活动打掩护。