a.  灭绝的，绝种的

a. 〔火山〕死的，不再活跃的 ≠ active

• extinction 

  n.  灭绝，绝种

  n. 〔某种类型的人、习俗、技能等的〕绝迹，消亡

• on the verge/edge/brink of extinction  濒临灭绝

• Dinosaurs have been extinct for millions of years. 恐龙已灭绝数千万年了。

• Their traditional way of life seems doomed to extinction. 他们的传统生活方式似乎注定要消亡。

• It speeds up the extinction of native languages. 语言的消亡

• They are on the verge of extinction because of pollution. 濒临灭绝

BrE /əˌbriːviˈeɪʃn/