【俚语】

Bad-mouth v. 诽谤，说坏话

【例句】

Divorced parents shouldn't bad-mouth each other in front of the kids.
离异的父母不应该在孩子们面前说彼此的坏话。

leave a bad taste in sb's mouth
给某人留下不愉快的记忆

【例句】

The way he was talking to the old man left a bad taste in my mouth.
他和那个老人说话的方式给我留下了不好的印象。

Big mouth 多嘴的人

【例句】

God you've got a big mouth! Don't you ever stop talking about other people's business?
天呐！你真是个多嘴的人！你能不能不谈别人的事情？

Mouthwatering （食品）令人垂涎的

【例句】

They’ve got a lot of mouthwatering desserts at the party last night.
昨晚的聚会上有很多让人垂涎的甜点。

By word of mouth
口头上地，口口相传地

【例句】

A: "How did you hear about our bakery?”
你从哪知道我们面包店的？
B: "Oh, by word of mouth. My dad told me about it.”
听说的。我爸告诉我的。