parasite

1. N-COUNT A parasite is a small animal or plant that lives on or inside a larger animal or plant, and gets its food from it. 寄生虫; 寄生植物

Kangaroos harbour a vast range of parasites. 袋鼠身上有各种各样的寄生虫。

2. N-COUNT If you disapprove of someone because you think that they get money or other things from other people but do not do anything in return, you can call them a parasite. 靠他人为生的人; 寄生虫[表不满]

...a parasite, who produced nothing but lived on the work of others. …一个什么都不做而靠他人的劳动为生的寄生虫。