查询结果:

adj. 两者挑一的
n. 可供选择的事物,替换物,选择对象

拆分: -alter-其它→交替→两者之一 + n + -ative形容词词尾   

例:
adj.  
You have a right to seek alternative employment. 你可以另谋高就。
We returned by the alternative road. 我们从另一条路回来的。
n. 
She had no alternative but to ask for a few days' leave. 实在不得已,她只好请几天假。
They have no alternative but to resign collectively. 他们除了集体辞职以外是别无选择了。