The Grammarphobia Blog

Fatal or mortal?

Q: I’d be grateful for your thoughts on whether “fatal” or “mortal” better describes a gunshot wound that someone dies of.

A: Either “fatal”  or “mortal” may describe a deadly wound. However, each adjective has several other meanings of its own.

“Fatal” may also mean, among other things, decisive (“a fatal moment”), causing failure (“a fatal design flaw”), and bringing ruin (“a fatal addiction”).

And “mortal” may mean implacable (“a mortal enemy”), of great intensity (“mortal fear”), subject to death (“all humans are mortal”), and so on.

At the end of its “fatal” entry, The American Heritage Dictionary of the English Language (5th ed.) compares four adjectives that “apply to what causes or is likely to cause death.”

  • Fatal describes conditions, circumstances, or events that have already caused death or are virtually certain to do so in the future: a fatal accidenta fatal illness.”
  • Deadly means capable of killing or of being used to kill: a deadly poisona deadly weapon.”
  • Lethal has a similar range, often with a suggestion of deliberate or calculated intent: execution by lethal injectionthe lethal technology of modern warfare.”
  • Mortal describes a condition or action that produces death, typically in a context of combat: a mortal wounddelivered a mortal blow.”

Getting back to your question, all the standard dictionaries we’ve checked define “fatal” and “mortal” similarly when used for an injury that causes, or is likely to cause, death.

As for the etymology, both “fatal” and “mortal” showed up in Middle English in the late 1300s, but it took “fatal” a few hundred years to get its sense of causing death

At first, “fatal” meant destined or fated, similar to the sense of fātālis, its Latin ancestor.

The earliest example in the Oxford English Dictionary is from Chaucer’s poem Troilus and Criseyde (circa 1374): “The fathel destyne, / That Joves hath in disposicioune.”

It wasn’t until the late 17th century, according to OED citations, that “fatal” came to mean “producing or resulting in death, destruction, or irreversible ruin, material or immaterial; deadly, destructive, ruinous.”

The dictionary’s first citation for the new sense is from The Roxburghe Ballads (1685–8): “O that my sorrows were ended, by the most fatalest hand.”

The adjective “mortal” came into English from Anglo-Norman, Middle French, and Latin sources. The ultimate source is the classical Latin mortālis (subject to death, human, transient), but in medieval Latin the word also came to mean causing death.

When “mortal” showed up in Middle English a few years after “fatal,” it meant “seeking to bring about the destruction of an adversary.”

The first OED example is from “The Knight’s Tale” in Chaucer’s The Canterbury Tales (c. 1385): “For I am Palamon thy mortal foo [foe].”

At the same time, “mortal” took on the sense we’re talking about: “Causing death, deadly, fatal; (now) spec. of a disease, wound, or blow.”

The first OED citation is from “The Tale of Melibeus” in The Canterbury Tales: “Thre of his olde foos … betten his wif and wounded his doghter with fyue [five] mortal woundes.”

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