The letter was a bluff.这封信是虚张声势。
The socialists have decided to call the opposition's bluff.社会党人已经决定让反对党摊牌了。
He said he would resign if he didn't get more money, but it was only a bluff.他说如果不给他加薪他就辞职,但那不过是虚张声势而已。