To describe an insignificant or contemptible person's futile and arrogant defiance, like a mad dog barking at the sun, which ultimately causes no harm.
那些散布谣言的小人，他们的言论不过是狂犬吠日，根本无法动摇事实。
The slanderous remarks of those petty people are merely like a mad dog barking at the sun, completely unable to shake the truth.
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