滅亡めつぼう Common Noun Irregular Intransitive English jmdict 1 noun (common) (futsuumeishi) noun or participle which takes the aux. verb suru intransitive verb downfall;ruin;collapse;destruction 仮に核戦争が起こったとすれば、人類は滅亡するだろう。 If a nuclear war were to break out, mankind would perish.