Definition of "mortal enemy" []

• An enemy who wants to kill you (noun)

WordNet. Princeton University. 2010.

• "Mallory Robinson, my mortal enemy and the bane of my existence, turned and whispered something to her friends, Jordan and Carrie."
• "She was a princess of great wit and generosity, but extremely bigotted to her sect, and a mortal enemy to the Christians, that is to say, to the Portuguese."
• "There is no such mortal enemy of genius as poverty except riches: a touch of the spur from time to time does good; but a constant rowelling disables."