filthy

Etymology

It is a Middle English formation, filthi, from filth and the adjective suffix -y.^[2][3][4][5]

Earliest recorded meaning

Dirty, unclean: c. 1384, in the early version of the Wycliffite Bible, of soiled clothes.^[2][5] Etymonline dates a sense "corrupt, sinful" to the late 12th century,^[6] and the Shorter Oxford also lists the moral sense first,^[7] but the OED, revising the entry in 2016, dates it to about 1400.^[2]

Semantic evolution

Etymonline, following the OED, notes that in early use the word was hardly stronger than modern dirty, but that it later became a violent expression of disgust.^[6] The figurative sense, morally foul or obscene, is recorded from about 1400,^[2] though Etymonline dates it to the 1530s.^[6] In 1533 filthy could describe a disgusting smell or taste and anything disgraceful or contemptible; later, in colloquial use, it became an intensifier.^[2] Johnson (1755) glossed it as "nasty; foul; dirty" and "gross; polluted", quoting Macbeth's "fog and filthy air".^[8] Weather has been filthy since 1600,^[2] a use Collins marks as chiefly British,^[9] and tempers since 1887;^[2] a filthy look dates from 1922.^[2] In Australian and New Zealand English a person filthy on someone is very angry with them (1986).^[2] Slang turned the word to money, from filthy lucre (1876 in the OED,^[2] 1905 in Green's^[10]), and, on the model of bad, to praise for something excellent (1987).^[10] In dialect it could also mean overgrown with weeds (Gloucestershire) or infested with vermin (northern England, Lincolnshire, Gloucestershire).^[11]

Timeline

• late 12th century – corrupt, sinful, in Etymonline's dating.^[6]
• c. 1384 – dirty, unclean.^[2][5]
• c. 1400 – morally foul, obscene;^[2] the 1530s in Etymonline.^[6]
• 1533 – offensive to the senses; disgraceful, contemptible.^[2]
• 1600 – of weather, wet and unpleasant.^[2]
• 1876 – the filthy, money.^[2]
• 1887 – of a temper, very bad.^[2]
• 1922 – of a look, showing disgust.^[2]
• 1986 – (Australia, New Zealand) very angry.^[2]
• 1987 – (slang) excellent.^[10]

Modern meaning

Adjective

1. Very dirty: Her boots were filthy after the walk.
2. Obscene or indecent.
3. Vile, underhanded: a filthy trick.
4. (informal, chiefly British) Very unpleasant, especially of weather.
5. (informal) Of a mood, very bad; of a look, expressing disgust or anger.

Adverb

1. (informal) Extremely, as in the set phrase filthy rich.

Word family

• filthily
• filthiness
• filthy lucre

Related words

• foul
• defile

Usage notes

In Wright's dialect dictionary filthy means covered with weeds in Gloucestershire and infested with vermin in the north of England, Lincolnshire and Gloucestershire; in Oxfordshire it is "outrageous, very bad" (a filthy temper), and in Devon it describes wet, foggy weather, as on Dartmoor.^[11]

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 r Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
5. ^ a b c Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
6. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
7. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
9. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
10. ^ a b c Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com
11. ^ a b Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)