perturb

Etymology

It is inherited from Middle English perturben,^[2][3] borrowed from Old French perturber, also pertourber and parturber,^[2][4][5] and directly borrowed from Latin perturbō (“to throw into confusion, disturb”).^[4][5][6][2] The French verb is recorded from about 1200,^[4] and Anglo-Norman had it by 1323–25.^[7] The Latin verb is formed from per- (“through, thoroughly”), from Proto-Indo-European *per- (“forward, through”),^[5] and turbō (“to disturb, confuse”),^[4][5][8] from turba (“turmoil, crowd”),^[5][6][9] perhaps from Ancient Greek τύρβη (túrbē).^[10] Barnhart notes that, since Chaucer has both words, his verb could be a back-formation from perturbation, recorded about 1380.^[6]

Earliest recorded meaning

To disturb, to cause disorder in: c. 1385, in Chaucer's Knight's Tale.^[4] Barnhart and the Middle English Dictionary cite Chaucer's Troilus and Criseyde for the same period, where the fear is of disturbing a woman's heart.^[6][2]

Semantic evolution

Etymonline notes that the Latin verb was used especially of states of mind.^[5] The OED separates physical and mental disturbance and finds the mental sense in Lydgate's Troy Book (c. 1425),^[4] while the Middle English Dictionary lists it first, also citing Chaucer.^[2] Middle English could also use the verb for breaking someone's rest, impairing a title to property or hindering a purpose.^[2] Chaucer has it only twice.^[11] The intransitive use is recorded from 1543.^[4] In the late 19th century science took it up, first for deflecting a celestial body from a regular orbit (1879, in R. A. Proctor), then for subjecting equations to a perturbation (1901).^[4]

Timeline

• c. 1385 – to disturb, to throw into disorder.^[4][5]
• c. 1425 – to trouble someone's mind.^[4]
• 1543 – intransitive, to disturb or agitate.^[4]
• 1879 – astronomy, to deflect a celestial body from its regular orbit.^[4]
• 1901 – physics and mathematics, to subject equations to a perturbation.^[4]

Meanings

Verb

1. To make someone anxious or uneasy; to trouble: News of the layoffs perturbed the staff.^[10][3][12]
2. To throw something into disorder or confusion: The dispute perturbed the whole council.^[3][12][4]
3. To alter a system from its normal state.^[10][8]
4. (physics, astronomy) To cause a planet or other body to deviate from a regular orbit.^{[10][3][12][4]}
5. (physics, mathematics) To subject a set of equations to a perturbation.^[4][8]

Word family

• perturbable
• perturbability
• perturbedness
• perturber
• perturbingly
• perturbment
• unperturbed

Related words

• disturb
• perturbation
• perturbative
• turbid
• imperturbable
• trouble

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f 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 Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c d e f g h i j k l m n o p Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
5. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b c d Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
7. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
8. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
9. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
10. ^ a b c d The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
11. ^ Benson, Larry D., Glossarial Concordance to Middle English (Chaucer, Gower), Johns Hopkins University, github.com/jhu-digital-manuscripts/gcme
12. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins