滅亡めつぼう
metsubō

Noun
Suru Verb

1. downfall; ruin; collapse; destruction

Intransitive
かりかく戦争せんそうこったとすれば、人類じんるい滅亡めつぼうするだろう。
karini kakusensōga okottato sureba jinruiwa metsubō surudarō.
If a nuclear war were to break out, mankind would perish.