This is a great chord, u can play it randomly on any key, like this one: VII13sus4=>V13sus4=>VI13sus4=>bV13sus4, the progression remains reasonable and good sounding...
adj.
Appropriate to a purpose.
有利的与目的相称的
Serving to promote one's interest:
出于私利的用来为自己利益服务的：
was merciful only when mercy was expedient.
只有仁慈对自己有利时才是仁慈的
Based on or marked by a concern for self-interest rather than principle; self-interested.
基于私利的依自身利害而定的，基于私利而非原则考虑的；自私自利
Obsolete
【废语】
Speedy; expeditious.
快速的；仓猝的
expedient
n.
Something that is a means to an end.
对策达到目的的方法
Something contrived or used to meet an urgent need.
权宜之计；应急的手段
See: makeshift
This kind of knowledge is easily available in the west, in China, we had to learn by our own intelligence and experience in most times, but it's still fun...