inactive

Etymology

It is formed from English in- + active, with in- meaning not.^{[2][3][4][5][6]} The OED compares the earlier unactive and the slightly earlier inactivity,^[2] and Etymonline suggests that the adjective may be a back-formation from that noun.^[3] Similar words are Medieval Latin inactivus (“ineffective”), used in a British source in 1620, and French inactif (1717).^[2] The sense in optics follows the French word as used by Biot in 1840, a term that Pasteur took over in 1848.^[2]

Earliest recorded meaning

Not active; without action, disinclined to act; inert, sluggish, passive: 1641, in Thomas Aston's Remonstrance against Presbitery.^[2][7] Etymonline dates the word to the 1640s.^[3] Other dictionaries date it later: Merriam-Webster to 1664,^[5][8] Random House to 1715–25,^[9] and Barnhart to 1725, in Pope's translation of the Odyssey.^[4]

Semantic evolution

Scientific senses followed the general one soon after: from 1665 the word was used of a substance that takes no part in a chemical process or has no effect, from 1673 also of a disease or infection that is present but produces no symptoms.^[2][7] From 1748 it described a person who takes no part in some activity.^[2] Johnson (1755) defined it only as not busy, not diligent, idle, indolent and sluggish.^[10] In 1848 physical chemistry adopted it for a substance that does not rotate the plane of polarized light, usually as optically inactive;^[2][6][7] later uses include members of the armed forces not on active service and elements with little or no radioactivity.^[8][11] As a noun, the inactive were inactive people as a class from 1772;^[2] from 1836 an inactive was an inactive person or thing, on the stock market a security that is not actively traded.^[2]

Timeline

• 1641 – not active, inert, sluggish.^[2]
• 1664 – first date in Merriam-Webster.^[5][8]
• 1665 – chemically unreactive, without effect.^[2]
• 1673 – of a disease, latent.^[2]
• 1725 – in Pope's Odyssey, Barnhart's first record.^[4]
• 1748 – of a person, not taking part in an activity.^[2]
• 1772 – noun, the inactive, inactive people.^[2]
• 1848 – optics, not rotating the plane of polarized light.^[2][7]

Meanings

Adjective

1. Not active; not moving, working or operating; idle or inert: The volcano has been inactive for centuries.^[11][5]
2. Leading a life with little activity; sedentary, or sluggish and indolent.^[5][8][11]
3. Not in use; out of operation.^[5][8]
4. Of members of the armed forces or their equipment: not on active service.^[11][8]
5. (chemistry) Having little or no reactivity; chemically inert.^[11][8][2]
6. Of a disease: latent or quiescent.^[8][2]
7. Not rotating the plane of polarized light; optically neutral.^[8][2][6]
8. Having little or no radioactivity.^[11]

Noun

1. A person or thing that is not active; on the stock market, a security that is not actively traded.^[2]

Word family

• inactively
• inactivity
• inactivate

Related words

• active
• unactive
• inaction

Usage notes

Random House distinguishes inactive, which simply means not acting or no longer acting, from dormant, inactive but able to be roused, inert, having no power of motion of its own, sluggish, slow in its natural activity, and torpid, with its powers suspended, as in hibernation.^[9]

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ 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
3. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
6. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ a b c d Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)
8. ^ a b c d e f g h i Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster
9. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
10. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
11. ^ a b c d e f Collins English Dictionary (2023), Glasgow: HarperCollins