soporific

Etymology

It is probably borrowed from French soporifique,^[2][3][4] formed in French from Latin sopor (“deep sleep”) and the suffix -ifique.^[3][4] The OED, which dates the French word to 1687, instead gives an unrecorded Latin *sopōrificus,^[5] and other dictionaries analyse it as the same noun with -fic.^[6][7][8][9] The noun is from Proto-Indo-European *swep- (“to sleep”),^[2] and is related to Latin somnus (“sleep”), the source of somnolent.^[3][2][5]

Earliest recorded meaning

Inducing sleep, of qualities: 1690, in Locke's Essay Concerning Human Understanding.^[5][3] Etymonline gives the 1680s,^[2] Merriam-Webster Unabridged 1665,^[4] and the Shorter Oxford and the Oxford Dictionary of English the mid 17th century.^[6][7]

Semantic evolution

The word followed older forms: soporiferous, "characterized by excessive sleep" from the 1580s and "soporific" from about 1600, and soporous, "causing deep sleep", from the 1680s.^[2] It soon moved from things that literally bring on sleep to dull writing and speech, from 1727 for books, talk and their authors;^[5] the Shorter Oxford treats this sense as a transferred one, "very tedious".^[6] It was used of drugs from 1775.^[5] In the other direction it came to mean "of or marked by sleepiness", from 1754, and "drowsy", of people, from 1841.^[5][6] The noun, a substance that brings on sleep, is recorded in 1699 in Boyer's dictionary in the OED,^[5] while Etymonline and Barnhart date it to 1722.^[2][3]

Timeline

• 1690 – of qualities, inducing sleep.^[5][3] Merriam-Webster Unabridged dates the sense to 1665.^[4]
• 1699 – noun, a substance that induces sleep.^[5] Etymonline dates it to 1722.^[2]
• 1727 – of books, talk or writers, tending to send one to sleep.^[5]
• 1754 – of the nature of sleep or sleepiness.^[5]
• 1775 – of drugs and medicines.^[5]
• 1808 – noun, a sleepy person (rare).^[5]
• 1841 – of people, drowsy.^[5]

Meanings

Adjective

1. Causing or tending to cause sleep: a soporific dose of cough syrup.^[4][10][5]
2. Very tedious, as if sending one to sleep: The lecture was thoroughly soporific.^[6][5]
3. Of or marked by sleepiness or lethargy.^[4][5]
4. Of a person, drowsy.^[10][5]
5. Tending to dull awareness or alertness.^[4]

Noun

1. A drug or other thing that brings on sleep.^[10][4][5]
2. (rare) A sleepy person.^[5][6]

Word family

• soporifically
• nonsoporific

Related words

• sopor
• soporiferous
• soporous
• somnolent
• -fic

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c d e f Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ a b c d e f g h Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c d e f g h i j k l m n o p q r s t Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ a b c d e f Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
8. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
9. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins