rigorous

Etymology

It is borrowed from Anglo-Norman rigorous and Middle French rigoreux, now rigoureux, formed from the noun for rigor with the suffix that gives English -ous.^[2][3] Etymonline takes the French word from Medieval Latin rigōrōsus,^[4] and Merriam-Webster and Dictionary.com borrow the English word directly from it.^[5][6] The Latin adjective, recorded from the 4th century for "severely cold" and then from the 14th, in British sources, for "severe",^[2] comes from Latin rigor (“stiffness, firmness”),^[2][4][7] from rigeō (“to be stiff”),^[8][4] from Proto-Indo-European *reig- (“to stretch”).^[8][4] The Anglo-Norman adjective is recorded from 1363 for "strict, harsh".^[9]

Earliest recorded meaning

Of a rule, action or judgement, extremely strict, harsh or severe: before 1425, in a sermon printed among the English works of Wyclif.^[2] Etymonline dates the word to the early 15th century, of persons and of laws.^[4]

Semantic evolution

The word first described rules and people who were strict to the point of harshness; this sense of a rule or action is now rare.^[2] Lydgate used it of a person before 1439, and Thomas More in 1513 of harsh weather, a sense French gained only in 1640.^[2] From about 1500 it also meant scrupulous and conscientious, and then from the mid 16th century demanding or austere, and precise or strictly accurate, now the commonest sense.^[2] A medical sense, accompanied by a chill, is recorded once, in 1597.^[2] Johnson (1755) defined it as "severe; allowing no abatement".^[10] In mathematics and logic a rigorous proof is one whose every step is made explicit.^[11]

Timeline

• before 1425 – of a rule or action, harsh, severe.^[2]
• before 1439 – of a person, strict, stern.^[2]
• before 1500 – scrupulous, conscientious.^[2]
• 1513 – of weather, harsh, bitterly cold.^[2]
• before 1564 – demanding; austere; precise, strictly accurate.^[2]
• 1597 – accompanied by a chill (obsolete).^[2]

Meanings

Adjective

1. Extremely thorough, careful and accurate: a rigorous survey of the data.^[11][5][2]
2. Strict, demanding or severe: The recruits faced a rigorous training programme.^[11][5][2]
3. Of weather or climate, harsh or extreme.^[11][2]
4. (mathematics, logic) Of a proof, making the validity of every step explicit.^[11]

Word family

• rigorously
• rigorousness
• overrigorous
• unrigorous

Related words

• rigor
• rigid

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 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
4. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
6. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
7. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
9. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
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 Collins English Dictionary (2023), Glasgow: HarperCollins