defunct
词根词缀：
defunct adj. 死亡的；失效的
de 否定 + funct 活动 → 不活动的 → 死亡的
dysfunction n. 机能失调
dys 坏 + function 功能 → 机能失调
function n. 功能
funct 活动 + ion 表名词 → 功能
functional adj. 能运转的；实用的
funct 活动，作用 + ion 表名词 + al …的，具有…性质的 → 能运转的；实用的
perfunctory adj. 草率的
per 坏 + funct 活动 + ory …的 → 活动〔因此〕搞砸了 → 草率的
数据来源：新东方英语词汇速记大全
相关例句：
"Practical men were often the slaves of some defunct economist," he wrote.
他写道：“实干家往往是一些已故经济学家的奴隶”。
They bought all their equipment from a defunct brewery in Manhattan.
他们那些设备都是从曼哈顿一家已经关闭的啤酒厂购买的。
And the train station becomes defunct.
然后火车站就不起作用了。
Such a merger would bring together two state-owned companies currently competing head-on in China, with saloons based on designs and technology acquired from defunct British carmaker MG Rover.
合并将使两家目前正面展开竞争的国有企业走到一起。这两家公司分别收购了英国破产汽车制造商MG罗孚（MG Rover）的设计和技术，以此为基础生产轿车。
Moreover, each may be traded, unlike the defunct mark.
此外，三种货币都能交易，不像已经不复存在的德国马克。
This schema object is defunct. No modifications are allowed until it is made active again.
此架构对象不起作用。在重新激活之前，不能进行任何改动。