Definition
Information obtained directly from the source or someone with firsthand knowledge.
從當事人口中得知
I didn't read it in the paper; I heard it straight from the horse's mouth.
我不是在報紙上看到的；我是直接從當事人那裡聽來的。
I heard about the company restructuring straight from the horse's mouth, the president.
我直接從總裁那裡聽到了公司重組的消息。
Don't believe the rumors; I got the accurate information straight from the horse's mouth, the manager.
不要相信謠言；我從經理那裡得到了準確的信息。