per-,完全的，-nic,伤害，杀害，词源同noxious,necrosis.引申词义有害的。

1. I did what I could, but her mother's influence was pernicious.

我已尽力了，但是她母亲贻害颇深。

2. The principle had been pernicious from beginning to end.

这条原则自始至终都是有害的.

3. Business may be troublesome, but idleness is pernicious.

事业虽扰人, 怠惰害更大.

4. They don't really, in their ivory towers, understand how pernicious drug crime is.

他们身处象牙塔中，并不真正了解毒品犯罪的危害有多大。

5. There is a pernicious culture of excellence: everything has to be not merely good but the best.

对于优秀存在着一种认识的误区：一切都务求最好。