a.

1. （火等）熄灭了的
   The volcano is extinct.

   这座火山是座死火山。

2. 消亡了的；破灭了的
   My hope of getting some employment was extinct.

   我要找到工作的希望落空了。

3. 绝种的，灭绝的
   The passenger pigeon is extinct.

   旅鸽已绝种。

4. （职位等）废除了的；（贵族称号等）无合法继承人的
5. （法令，风俗等）过时的，失效的

adj.

1. (of a species or other large group) having no living members.
   ▸no longer in existence.
   ▸(of a volcano) not having erupted in recorded history.
2. (of a title of nobility) having no valid claimant.