probable

Etymology

It is partly borrowed from Middle French probable, partly probābilis (“that may be proved, credible, worthy of approval”),^[2][3][4] formed with the suffix -bilis (English -able) on probō (“to test, approve, prove”),^[2][5][6] the verb behind prove, probe, probate and probation.^[5] Weekley traces the verb further to probus (“good”), the source of probity.^[7] In French the adjective is recorded from the late 14th or early 15th century.^[2]

Earliest recorded meaning

Worthy of acceptance or belief, believable, sometimes in the bad sense "plausible, specious": a1387, in John Trevisa's translation of Higden's Polychronicon.^[2][4] Etymonline gives the late 14th century and the meanings "likely, reasonable, plausible, having more evidence for than against".^[3]

Semantic evolution

The Latin adjective had already moved from "provable" to "approved": Trench (1859) notes that Cicero's probabilis orator is an approved orator, and that 17th-century scholarly writers often used probable in that way, though by his day it meant only "likely".^[8] English had the senses "worthy of trust", of a person (1596–1682), and "demonstrable, provable" (1485–1865), both now obsolete.^[2][9] The sense that won out, having an appearance of truth and so likely to happen or be the case, is recorded from ?a1425,^[2] although Barnhart puts the first clear use of "likely to occur" in Shakespeare's Antony and Cleopatra (1606).^[4] Johnson (1755) defined it as "likely; having more evidence than the contrary".^[10] The legal phrase probable cause, reasonable grounds, is attested from the 1670s.^[3] As a noun, the word meant a probable event from 1638, a likely winner or candidate from 1868, and in the Second World War an aircraft or submarine probably destroyed (1940).^[2][11]

Timeline

• a1387 – worthy of belief, acceptable.^[2]
• ?a1425 – likely to happen or to be the case.^[2]
• 1485 – demonstrable, provable (obsolete by 1865).^[2][9]
• 1596 – of a person, trustworthy (obsolete by 1682).^[2]
• 1606 – likely to occur, in Shakespeare.^[4]
• 1638 – noun, a probable event.^[2][11]
• 1670s – probable cause.^[3]
• 1868 – noun, a likely winner or candidate.^[2]
• 1940 – noun, an aircraft or submarine probably destroyed.^[2]

Modern meaning

Adjective

1. Likely to be true or to happen, though not certain: Rain is probable by the afternoon.
2. Supported by evidence that is fairly convincing but not conclusive: the probable cause of the delay.

Noun

1. A person likely to be chosen for a team or to win or take part in something.
2. (military, historical) An enemy aircraft or ship recorded as probably destroyed.

Word family

• probability
• probably
• probable error
• probable cause

Related words

• prove
• probe
• probate
• probation
• probity
• likely

Usage notes

Trench pointed readers to a distinction between probable and likely, and probability and likelihood, drawn in Garden's Dictionary of Philosophical Terms.^[8]

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
6. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
7. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
8. ^ a b Trench, Richard Chenevix (1859), A Select Glossary of English Words Used Formerly in Senses Different from Their Present, London: John W. Parker
9. ^ a b Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)
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 Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster