In the first moment of fear, he called, indeed, as loud as he could—"You impudent little blackguard!"

在他害怕那一刻，用最大的声音喊道：“你这个无礼的小坏蛋！”

A blackguard is a scoundrel.

黑色卫士(blackguard)指的是一个恶棍。

I think you are a blackguard.

我觉得你是个大坏蛋。

I am blackguard, I fear who.

我是流氓，我怕谁。

She is an old blackguard of a woman.

她是一个恶毒的老妇人。