arduous

Pronunciation

• UK: /ˈɑː.djʊ.əs/, /ˈɑː.d͡ʒʊ.əs/^[1]
• US: /ˈɑɹ.d͡ʒu.əs/^[1]

Etymology

It is borrowed from Latin arduus (“high, steep; difficult”),^{[2][3][4][5][6]} with the suffix -ous.^[5][4][7] Barnhart suggests that the borrowing may have been influenced by Old French ardu (“steep, difficult”), recorded in 1365.^[4] The Latin adjective is cognate with Old Irish ard (“high”), Welsh hardd (“handsome”), Avestan ərədva- (“high”) and Tocharian A orto (“up”),^[4][8][9] and Ayto relates it to Ancient Greek ὀρθός (orthós, “straight, upright, correct”), as in orthodox.^[10][9] Etymonline traces it to Proto-Indo-European *eredh- (“high”),^[2][9] Barnhart to *er(ə)d- (Pokorny 339).^[4]

Earliest recorded meaning

Hard to accomplish, needing much labour: 1538 according to Barnhart,^[4] the 1530s in Etymonline^[2] and the mid-16th century in the Shorter Oxford.^[11] The OED, in an entry not revised since 1885, has no record before 1711, when Pope used it of lofty, steep paths in his Essay on Criticism.^[5]

Semantic evolution

Ayto explains that the Latin word first meant high or steep, and "difficult, laborious" was a later metaphor.^[10] In English the order is reversed: the sense "difficult" is recorded from the 1530s, and the literal sense "high, steep, hard to climb" only from 1709 according to Etymonline, or 1711 in the OED.^[2][5] Johnson (1755) put "lofty; hard to climb" first, quoting Pope, and "difficult" second.^[12] From 1753 the word was transferred to the effort itself, meaning strenuous or energetic.^[5] The Century Dictionary, quoted by Etymonline, held that what is arduous demands more energy and endurance than what is merely hard, and that the old idea of steep climbing is still felt in it.^[2]

Timeline

• 1538 – hard to accomplish, laborious.^[4] Etymonline dates it to the 1530s; the OED's first record of this sense is Pope's translation of the Iliad (1718), the date Merriam-Webster also gives.^[2][5][8]
• 1709 – literally high, steep, hard to climb.^[2] The OED's first record is Pope's, in 1711.^[5]
• 1753 – of an effort, strenuous or energetic.^[5]

Meanings

Adjective

1. Needing great physical or mental effort; strenuous or laborious: an arduous climb to the summit.^[13][8][5]
2. Hard to endure; harsh: arduous winters in the north.^[13]
3. Steep and hard to climb or get over.^[13][5][12]

Word family

• arduously
• arduousness
• unarduous

Related words

• orthodox
• ortho-

Usage notes

Ayto points out that arduous has no connection with ardour, which comes from Latin ardēre, to burn.^[10]

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. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b c d e f g h i j Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
8. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ a b c Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
11. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
12. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
13. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins