1N-COUNT 水蛭;蚂蟥 A leech is a small animal which looks like a worm and lives in water. Leeches feed by attaching themselves to other animals and sucking their blood. 水蛭;蚂蟥
2N-COUNT 吸血鬼;寄生虫 If you describe someone as a leech, you disapprove of them because they deliberately depend on other people, often making money out of them. 吸血鬼;寄生虫 [disapproval]
They're just a bunch of leeches cadging off others!