打开最近刚被封的zlibrary网站即可看到：This website has been seized.（该网站已被查封）

所以，此处“查封”一词用的是seized。

seized一词的原形动词为seize：

seize作为及物动词有“没收，查封”这层含义，英文释义为： If a government or other authority seize someone's property, they take it from them, often by force. 没收; 查封

例如：

•  Police were reported to have seized all copies of this morning's edition of the newspaper.

 据报道警方已没收了该报纸今早所有的出刊。

（释义及例句来源：《柯林斯英汉双解大词典》）

顺便提一下，当想要表达“查封（扣押）财产”时，还可以用poinding一词。poinding在《元照英美法词典》中，给出如下释义：

查封；扣押财产 〈苏格兰〉

一种法院判决后债权人强制债务人清偿债务的程序。先由法院告知债务人付款，如债务人拒不履行债务，则由执法官员进入债务人家中或其营业场所，编制财产目录并分别估算其价值，然后向法院报告。法院可批准将财产公开拍卖或直接判归债权人。

poinding一词韦氏词典给出的释义为: a process by which a creditor seizes movable property so as to become vested with its title and the right of sale or appropriation in satisfaction of a debt

如：

poinding of the ground

(1)查封、扣押地上财产

(2)查封、扣押和出售债务人地上财产的命令