extinct個verb係乜野?

verb=exterminate
noun=extinction
adjective=extinct

Extinguish - verb
Extinct - adjective
Extinction - noun

an extinct animal (絕種動物)
The fire was slowly extinguished. (火慢慢被救熄)
extinction of a species (一種種類(動物/植物)的滅絕)

英文字的 part of speech 當然重要, 同時我們也要留意生字的用法
如果你想話 "恐龍已絕種了"
可考慮不用 extince 的 verb form, 而寫成
"Dinosaur is extinct."