mortal 

mortal - a 
subject to death; "mortal beings" 
unrelenting and deadly; "mortal enemy" 

wordplays

You are a mortal because you are mortal. This means that you are an individual destined to die because you are susceptible to death.

The word mortal has one of the most ancient genealogies of any word in English or any other language. It is related to English words like "murder" and "mortuary," and to the French, Italian, Spanish, and Russian words for "death." Something that can kill you can also be described as mortal. If you're in mortal danger, you're in a deadly situation. Action heroes often think they are dealing their enemy a mortal blow, but sometimes the enemy manages to come back to life. People are called mortals because at some point, they die.

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MORTAL

mortal - a 
subject to death; "mortal beings" 
unrelenting and deadly; "mortal enemy" 

wordplays

Synonyms

dire, fatal, grievous, grim, lethal, malignant, terrible, bitter, ending, extreme, grave, great, killing, last, terminal

thesaurus

Examples

The undecided question as to whether the wound inflicted at Borodino was mortal or not had hung over Kutuzov's head for a whole month.

Uneasy, he also realized he had to focus on mopping up the rest of his mess in the mortal world, so he could start to address the underworld.

The two types of beings had last brought their war to the mortal realm during the time of the Schism, when they'd almost destroyed the universe.

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Etymology

late 14c., "deadly, destructive to life; causing or threatening death" (of illness, poisons, wounds, etc.); also, of persons or the body, "doomed to die, subject to death;" from Old French mortel "destined to die; deserving of death" and directly from Latin mortalis "subject to death, mortal, of a mortal, human," from mors (genitive mortis) "death."

etymonline