相互保证毁灭xiāng hù bǎo zhèng huǐ mièxianghubaozhenghuimiemutual assured destructionCharacters in this word互mutually, reciprocally保to safeguard, to protect, to defend, to care for毁to damage, to ruin灭to extinguish相mutual, reciprocal证to prove, to verifyStudy it in Yanamino