“mouth off”很多人一看就觉得是闭嘴的意思，其实它的意思是“高谈阔论，信口开河，顶嘴”。

【例句】
Powell was his usual reassuring presence, urging senators not to mouth off.
鲍威尔仍是平日那副老神在在的样子，他呼吁参议员信口开河。

If he hadn't shot his mouth off, things couldn't have been so awkward.
要不是他多嘴，事情也不至于搞僵。