unhealthy

Etymology

It is formed from English un- + healthy.^[2][3][4][5] It was preceded by unhealthsome (1540s) and unhealthful (1570s),^[5] and Middle English had the noun unhealth, from Old English unhælþ.^[5]

Earliest recorded meaning

Harmful to health: Merriam-Webster dates the word to 1595, and Etymonline to the 1590s.^[4][5] The OED's first quotation, from 1600 in Hakluyt's Principal Navigations, describes places and climates that were bad for health.^[2]

Semantic evolution

From 1611, in Cotgrave's dictionary, the word was used of people, "sickly, not in good health",^[2][5] the sense Johnson (1755) gave as "sickly; wanting health".^[6] Figurative use followed in 1821, in Charles Lamb,^[2] and a medical sense, diseased or morbid, in 1862.^[2] In the First World War soldiers called a place under heavy fire unhealthy, meaning dangerous,^[2][7][5] and Collins keeps the informal sense "risky".^[8]

Timeline

• 1595 – harmful to health (Merriam-Webster; the OED has 1600).^[4][2]
• 1611 – of people, sickly.^[2]
• 1821 – figurative.^[2]
• 1862 – in pathology, diseased.^[2]
• 1915 – military slang, dangerous.^[2]

Modern meaning

Adjective

1. Not in good health; sickly: an unhealthy calf.
2. Harmful to health: He gave up his unhealthy diet of fried food.
3. Showing or resulting from ill health: a pale, unhealthy look.
4. Morbid or unwholesome: an unhealthy interest in crime.
5. (informal) Dangerous or risky.

Word family

• unhealthily
• unhealthiness

Related words

• health
• healthy
• unhealthful
• whole
• hale

Usage notes

Etymonline quotes Eliza Leslie's Behaviour Book (1839), which held that food should be called wholesome or unwholesome, not healthy or unhealthy: a pig may be healthy while alive, but pork can have no health.^[5]

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
4. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
7. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
8. ^ Collins English Dictionary (2023), Glasgow: HarperCollins