These people give me the creeps. Riffraff!

这些人使我起鸡皮疙瘩。真是一群痞子！

An ordinary girl meets a riffraff boy at high school.

相貌平平的普通女孩遭遇了高中校园痞子。

Haven't you been told it's dangerous to drive alone through all that riffraff?

没有人告诉过你一个人通过那段路是很危险的吗？

You hang around with riffraff like the Weasleys and that Hagrid and it'll rub off on you.

你如果跟像韦斯莱家或海格这样不三不四的人混在一起，你会受到影响的。

In fact, the proposed park was rejected by the city of Anaheim on the grounds that it would only attract riffraff.

而事实上，他的公园议案也被阿纳海姆市拒绝，因为他们认为这样的公园只会招致群氓。