Talk through one's hat(the back of one's neck).
eg: Stuff and nonsense! Don 't try to fool me.
反义词:引经据典 Give chapter and verse.
参考例句：His sermons were delivered without book. 他的讲道文从不引经据典
同义词：胡言乱语 Talk nonsense
参考例句：Did you ever hear such nonsense 你听过这种胡言乱语吗