mutter

/ˈmətər/

a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech

中文释义：咕哝；低语

The old man gave a mutter of discontent when the price was announced.

当价格公布时，老人不满地咕哝了一声。

She heard a mutter from the back of the courtroom during the verdict.

在宣读判决时，她听到法庭后面传来一阵低语。