形容一些不好的性格

1. have an ax to grind
心怀叵测

如：She always has an ax to grind. You should take whatever she says with a pinch of salt.
她总是心怀叵测，对她说的话你得多留神 。

have one’s heart in the right place
心数不正

如：He doesn’t have his heart in the right place. He would find every opportunity to stab in the back of others.
他的心数不正，动不动就在别人的背后捅刀子。

3. stab in the back
背后捅刀子

如：I was taken aback and didn’t think Zhang would stab me in the back. I placed too much trust in her.
我万万没想到张某会在背后捅我一刀。我过去太信任她了。

4. badmouth somebody
说某人的坏话

如：I’ve never badmouthed anyone.
我从来没说过任何人的坏话。

5. smite with the tongue
血口喷人

如：Don't offend her. She always smites with the tongue.
千万别得罪她，她经常血口喷人。

k with one’s tongue in one’s cheek
假惺惺的说

如：I feel sick of her. She always speaks with her tongue in her cheek.
我特别讨厌她。她说话总是假惺惺地。

发牢骚

如：I’m really bored with his sitting there doing nothing but beefing.
他坐在那里什么事也不干，总是发牢骚，真烦死人。

7. go back on one’s words
说话不算数

如：We cannot account on him. He always goes back on his words.
他那个人说话从不算数,我们可不能依靠他。

8. bite the hand that feeds one
恩将仇报

如：Don’t you know she’s the one that would bite the hand that feeds her?
你难道不知道她是个恩将仇报的人？

the gall to do
厚着脸皮去干

如：How can you have the gall to complain about other people’s being lazy?
你怎么能厚着脸皮去抱怨说别人不勤快？