Etymograph

English

internecine

Internecine comes from Latin internecīnus ‘deadly’, from internecium ‘a massacre, slaughter’, and ultimately from Proto-Indo-European *neḱ- ‘perish, disappear’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*neḱ-1‘perish, disappear’reconstructed
  2. Proto-Italicc. 1500–700 BCE*neks2reconstructed
  3. Latinc. 75 BCE–200 CEnex1‘murder, slaughter, killing, violent death’
  4. Latinc. 75 BCE–200 CEnecō3‘kill’
  5. Latinc. 75 BCE–200 CEinternecō4‘to kill, destroy’
  6. Latinc. 75 BCE–200 CEinternecium4‘a massacre, slaughter’
  7. Latinc. 75 BCE–200 CEinternecīnus5‘deadly’
  8. Englishearliest quotation c. 1900internecine5

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin neco
  2. 2 Wiktionary, Latin nex
  3. 3 Wiktionary, Latin interneco
  4. 4 Wiktionary, Latin internecinus
  5. 5 Wiktionary, English internecine
  6. Earliest quotation in Wiktionary’s entry: c. 1900, Mark Twain, Autobiography of Mark Twain: “During the year of my engagement — 1869 —…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*neḱ-Wiktionary, Latin neco‘perish, disappear’reconstructed
  2. Proto-Italicc. 1500–700 BCE*neksWiktionary, Latin nexreconstructed
  3. Latinc. 75 BCE–200 CEnexWiktionary, Latin neco‘murder, slaughter, killing, violent death’
  4. Latinc. 75 BCE–200 CEnecōWiktionary, Latin interneco‘kill’
  5. Latinc. 75 BCE–200 CEinternecōWiktionary, Latin internecinus‘to kill, destroy’
  6. Latinc. 75 BCE–200 CEinterneciumWiktionary, Latin internecinus‘a massacre, slaughter’
  7. Latinc. 75 BCE–200 CEinternecīnusWiktionary, English internecine‘deadly’
  8. Englishearliest quotation c. 1900internecineWiktionary, English internecine. Earliest quotation in Wiktionary’s entry: c. 1900, Mark Twain, Autobiography of Mark Twain: “During the year of my engagement — 1869 —…”

The story

In Latin, the sememe 'between' was here not expressed by the prefix, it instead either had a somewhat emphatic meaning or meant "down, under", comparable to its use in other Latin terms related to death: see interficiō and intereō. The English current sense is thus a reanalysis of the Latin through English inter-.

Full etymology on Wiktionary

Linked words

through Proto-Indo-European *neḱ- ‘perish, disappear’

innocent, innocence, nuisance, obnoxious, innocuous, noxious, nectar, necropolis, 18 more

Today it means

adj Mutually destructive; most often applied to warfare.

Sources

Sources: Wiktionary, “internecine”; the older steps come from the Wiktionary entries for Latin neco, Latin nex, Latin interneco, Latin internecinus. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.

Etymograph / Proto-Indo-European *neḱ- / internecine

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