颓败的英文：
decadent; declining

decadent是什么意思：
n. 颓废派
adj. 颓废的

decade; decennium
十年

It was the most stunning surprise of the decade.
这是十年来最令人吃惊的事情。

Nine plus one is a decade.
9加1是10。

His face was a decadent face.
他的脸是一张颓废派艺术家的脸。

The decadence of morals is bad for nation.
道德的堕落对于国家是不利的。

declining是什么意思：
adj. 下滑的，衰退的
v. [decline] 的现在分词形式；下降，衰退

sink into a decline
开始衰落，衰弱下去，体力衰退

The population is on the decline.
人口在减少。

The decline of literature indicates the decline of a nation.
文学的衰落表明一个民族的衰落。

Tax cheats have declined.
偷税逃税事件已有所减少。

to refuse with thanks; to politely decline
婉谢