hydrophobic

Etymology

It is borrowed from Late Latin hydrophobicus (“of hydrophobia”),^[2][3][4][5] from Ancient Greek ὑδροφοβικός (hudrophobikós),^[2][6][3] the adjective of ὑδροφοβία (hudrophobía, “horror of water; rabies”),^[6][2] which comes from ὑδρόφοβος (hudróphobos, “dreading water”),^[2][7] formed from ὕδωρ (húdōr, “water”) and φόβος (phóbos, “fear”).^[6][7] Etymonline traces the first part to Proto-Indo-European *wed- (“water; wet”).^[7] The OED compares French hydrophobique and, earlier, Old French ydroforbique.^[2] Etymonline instead takes the English word as formed from hydrophobia and -ic,^[7] and Dictionary.com from hydrophobe with the same suffix.^[8]

Earliest recorded meaning

Of, relating to, or suffering from hydrophobia, that is rabies: 1807, in the Medical and Physical Journal.^[2][3][7]

Semantic evolution

Hydrophobia was so called because human sufferers from rabies show an aversion to water and have trouble swallowing it,^[7][6] and the adjective first belonged to that disease.^[2] From 1864 it was also used as a noun for a person with hydrophobia.^[2] In the 20th century the literal "water-fearing" meaning was taken up in chemistry: from 1915 for a colloid that does not readily take up water, and since 1938 generally for substances that repel water or are not wetted by it.^[2] The chemical sense now comes first in the Concise Oxford and Collins.^[9][10]

Timeline

• 1807 – relating to or suffering from hydrophobia (rabies).^[2][3][7]
• 1864 – noun, a person with hydrophobia.^[2]
• 1915 – in physical chemistry, of a colloid that does not readily take up water.^[2]
• 1938 – tending to repel water or not to absorb it.^[2]

Meanings

Adjective

1. (chemistry) Tending not to mix with, dissolve in or be wetted by water; lacking an affinity for water: Oil is hydrophobic, so it floats in a separate layer.^{[10][3][9][2]}
2. Resistant to wetting; repelling water: a hydrophobic coating on the lens.^[3][2]
3. Of, relating to or suffering from hydrophobia (rabies).^[10][3][2]

Word family

• hydrophobicity
• nonhydrophobic

Related words

• hydrophobe
• hydrophobia
• hydrophilic
• phobia

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 o p Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ Gove, Philip Babcock, ed. (1961), Webster's Third New International Dictionary of the English Language, Unabridged, Springfield, Mass.: G. & C. Merriam
6. ^ a b c d Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
7. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
8. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
9. ^ a b Soanes, Catherine; Stevenson, Angus, eds. (2004), Concise Oxford English Dictionary, 11th ed., Oxford: Oxford University Press
10. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins