deadly

Etymology

It is inherited from Middle English dedli, earlier deedlich,^[2][3][4] inherited from Old English dēadlīc (“mortal, subject to death; causing death”),^[5][3][6][7] formed from Old English dēad + -līc.^[4][3] The Old English adjective comes from the word that gave dead, which goes back to Proto-Germanic *daudaz (“dead”).^[5][8] Wiktionary reconstructs *dauþalīkaz for the whole word.^[1] Similar formations are Old Frisian dādlik, Middle Dutch dodelijc, Dutch dodelijk, Middle Low German dōtlik, Old High German tōdlīh, German tödlich, Old Norse dauðligr, Swedish dödlig and Danish dødelig; the OED explains that these were mostly built on the words for death, though the forms for "death" and "dead" overlap in all these languages.^[9] The adverb is inherited from Middle English deedliche, inherited from Old English dēadlīce, from the adjective.^[3][4]

Earliest recorded meaning

Old English used the word both for what is subject to death, as in Ælfric's Catholic Homilies,^[9] and for what causes death, as in the translation of Orosius: Rómáne deádlícne sige gefóran, "the Romans gained a deadly victory".^[7][9] Dictionary.com dates the word to before 900.^[10]

Semantic evolution

The passive sense "mortal" lasted a long time: deedli is the regular word in Wycliffe's Bible where later versions have mortal, as in "Elye was a deedli man lijk us" (James 5:17).^[11] The OED records it until 1906, and "in danger of death" until 1857,^[9] but the active sense has taken over, so that one no longer speaks of a deadly body.^[11] Etymonline dates the sense "having the capacity to kill" to the late 14th century and notes that Old English also had deaðbærlic and deaðberende for it,^[5] while the OED, revised in March 2024, finds that sense in Old English, in the Lindisfarne Gospels.^[9] From the early 13th century the word also described a sin that deprives the soul of grace, the opposite of venial.^[9] Fights and enemies were called deadly from about 1275, when the aim to kill was in view,^[9] and Johnson (1755) gave two senses, "destructive; mortal; murtherous" and "mortal; implacable".^[12] The sense "resembling death" appears in the Middle English of the Cursor Mundi, and the figurative sense "harmful" in 1653.^[9] The adverb became an intensifier in the late 16th century,^[9] part of a wider pattern of describing intensity in terms of the absence of life that dates from the same period.^[13] In English dialects both adjective and adverb could mean "very, exceedingly", for good or bad things alike, and in Cheshire a fire that had burned low had "gone very deadly".^[14] Modern dictionaries add "extremely boring" and "extremely accurate",^[10][15] and slang, originally US Black and campus use and later also Irish, has it for "excellent".^[16]

Timeline

• Old English – subject to death; in danger of death; causing death; able to kill.^[9][7]
• c. 1225 – of an object, lifeless (obsolete by 1500).^[9]
• c. 1225 – of a sin, depriving the soul of grace.^[9]
• c. 1275 – of a conflict or enemy, aiming to kill.^[9]
• c. 1330 – adverb, intensely, to the death.^[9][2]
• before 1400 – of darkness or silence, resembling death.^[9]
• 1578 – in names of poisonous plants.^[9]
• 1589 – adverb, extremely, excessively.^[9]
• 1653 – figurative, harmful, pernicious.^[9]
• 1907 – slang, excellent, first-rate.^[16]

Meanings

Adjective

1. Causing or able to cause death; lethal or fatal: a deadly toxin.^[17][3][18]
2. Aiming to kill or destroy; implacable: the two deadly rivals.^[3][18]
3. Resembling death: a deadly stillness.^[9][18][17]
4. Destructive in effect, or tending to take away vitality or force.^[18][9]
5. Extremely accurate or effective: a deadly marksman.^[10][15]
6. (informal) Extremely boring: The lecture was deadly.^[17][10][15]
7. Complete, total, as in deadly earnest.^[15]
8. (theology) Of a sin, mortal, as opposed to venial.^[9]
9. (slang) Excellent, first-rate.^[16]
10. (obsolete, Old English–1906) Subject to death, mortal.^[9][3][11]
11. (obsolete, Old English–1857) In danger of dying.^[9][3]
12. (obsolete, c. 1225–1500) Inanimate, lifeless.^[9][3]

Adverb

1. Extremely, excessively: deadly dull.^[3][9]
2. In a way that resembles death: deadly pale.^[3][17][9]
3. (archaic) In a way that causes death; mortally.^[3][9]
4. (archaic) Implacably, to the death.^[3][19]

Word family

• deadliness
• nondeadly
• deadly sin
• deadly nightshade

Related words

• dead
• death
• deathly

Usage notes

A rhetoric manual of 1886, quoted by Etymonline, separates the word from deathly: deadly is what inflicts death, deathly what resembles it, so a deadly poison but a deathly paleness.^[5] Trench likewise contrasted it with mortal: deadly is always active in his day, while mortal is more often passive, as in a mortal body.^[11]

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
3. ^ a b c d e f g h i j k l m Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
5. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
7. ^ a b c Bosworth, Joseph; Toller, T. Northcote (1898), An Anglo-Saxon Dictionary, Oxford: Clarendon Press; Toller, T. Northcote (1921), Supplement
8. ^ Kroonen, Guus (2013), Etymological Dictionary of Proto-Germanic, Leiden Indo-European Etymological Dictionary Series 11, Leiden / Boston: Brill
9. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z 27 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
10. ^ a b c d Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
11. ^ a b c d Trench, Richard Chenevix (1859), A Select Glossary of English Words Used Formerly in Senses Different from Their Present, London: John W. Parker
12. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
13. ^ Mapping Metaphor with the Historical Thesaurus, University of Glasgow, mappingmetaphor.arts.gla.ac.uk
14. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)
15. ^ a b c d Pearsall, Judy, ed. (1998), The New Oxford Dictionary of English, Oxford: Clarendon Press
16. ^ a b c Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com
17. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins
18. ^ a b c d The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
19. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press