illness

Etymology

It is formed from English ill + -ness.^[2][3][4][5] Ill is from Old Norse illr (“evil, bad; hard, difficult”),^[3][2][6][7] a word of unknown further origin that is not related to evil.^[3][2]

Earliest recorded meaning

Bad moral quality, wickedness, depravity: about 1500, in Melusine.^[2][3]

Semantic evolution

The word first meant moral badness (about 1500 to 1718) and then unpleasantness or harmfulness (about 1595 to 1718).^[2][4] Its base ill had meant "morally evil" from the 12th century and "sick" only from the 15th,^[8][7] and the noun followed: "disease, bad health" is recorded from 1692 in the OED;^[2] Etymonline has the 1680s^[3] and the Shorter Oxford the late 17th century.^[4] Johnson (1755) still listed badness of any kind first, and quoted Macbeth for "wickedness".^[9] In Yorkshire and Lincolnshire an illness was an infectious epidemic, as against an ordinary cold.^[10]

Timeline

• c. 1500 – wickedness, depravity (obsolete by 1718).^[2][3]
• c. 1595 – unpleasantness, harmfulness (obsolete by 1718).^[2]
• 1692 – bad health; a disease, sickness.^[2]

Meanings

Noun

1. A disease or ailment: a long illness.^[11][12]
2. The state of being in poor health; sickness.^[11][2]
3. (obsolete, c. 1500–1718) Wickedness, depravity.^[11][12][2]
4. (obsolete, 1595–1718) Unpleasantness, harmfulness.^[2][4]

Word family

• mental illness

Related words

• ill
• sick
• sickness

Usage notes

Etymonline quotes the Century Dictionary (1889): sick and illness had long been near synonyms, but British usage was coming to limit sick and sickness to nausea, while American usage regarded illness as a somewhat more refined and vaguer word.^[3]

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
7. ^ a b Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
8. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
9. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
10. ^ 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)
11. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins
12. ^ a b Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster