Iraq was Iran's mortal enemy.

伊拉克曾是伊朗的死敌。

youdao

But, English does have one possible mortal enemy-itself.

但是，英语的确有一个可能的致命敌人这就是它自身。

youdao

Eventually he arranged for Flamsteed's work to be seized and prepared for publication by Flamsteed's mortal enemy, Edmond Halley.

最后，他指使夫莱姆斯梯德的冤家对头爱德蒙·哈雷夺得夫莱姆斯梯德的工作成果，并且准备出版。

youdao

Deflation became the mortal enemy as people removed their cash from banks and hoarded it.

CNN: Commentary: Is it 1929 all over again?

Excess inventories are the mortal enemy of prices, and I count 1.9 million vacant houses over and above the normal working level.

FORBES: Prepare For A Stock Market Plunge