Definition of foulnext
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foul

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verb

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Synonym Chooser

How does the adjective foul differ from other similar words?

Some common synonyms of foul are dirty, filthy, nasty, and squalid. While all these words mean "conspicuously unclean or impure," foul implies extreme offensiveness and an accumulation of what is rotten or stinking; it can also describe, for example, loathsome behavior.

a foul-smelling open sewer
a foul story of lust and greed

When can dirty be used instead of foul?

Although the words dirty and foul have much in common, dirty emphasizes the presence of dirt more than an emotional reaction to it or, figuratively, stresses meanness or despicableness.

a dirty littered street
don't ask me to do your dirty work

When could filthy be used to replace foul?

The meanings of filthy and foul largely overlap; however, filthy carries a strong suggestion of offensiveness and typically of gradually accumulated dirt that begrimes and besmears. Figuratively, it can also describe disgusting obscenity.

a stained greasy floor, utterly filthy
filthy street language

How is nasty related to other words for foul?

Nasty applies to what is actually foul or is repugnant to one expecting freshness, cleanliness, or sweetness; in practice, however, nasty is often weakened to the point of being no more than a synonym of unpleasant or disagreeable. When used figuratively, nasty implies a peculiarly offensive unpleasantness.

it's a nasty job to clean up after a sick cat
had a nasty fall
his answer gave her a nasty shock
a stand-up comedian known for nasty humor

When would squalid be a good substitute for foul?

In some situations, the words squalid and foul are roughly equivalent. However, squalid adds to the idea of dirtiness and filth that of slovenly neglect. Distinctively, its figurative use implies sordidness as well as baseness and dirtiness.

squalid slums
engaged in a series of squalid affairs

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of foul
Adjective
In an effort to stymie the foul smell, part of the facility is wrapped in plastic sheeting while large fans spray odor-control mist around the warehouse. Celina Tebor, CNN Money, 8 Aug. 2026 Their crimes were discovered after neighbors in October 2023 reported smelling a foul odor. Jeanine Santucci, USA Today, 8 Aug. 2026
Verb
Injury updates Miguel Rojas (ankle) was available off the bench despite exiting Saturday’s game after fouling a ball off his foot. Joaquin Ruiz, Los Angeles Times, 3 Aug. 2026 In the seventh inning, a black squirrel appeared on the field and ventured from left field to foul territory just in front of the third-base coaches’ box. Cody Stavenhagen, New York Times, 28 July 2026 See All Example Sentences for foul
Recent Examples of Synonyms for foul
Adjective
  • In a series distinguished by copious disgusting battle scenes, Ormund co-stars in one of its very grossest—a gross-on-gross-on-gross flambé—and almost gets in one last barf.
    Sarah Larson, New Yorker, 10 Aug. 2026
  • His central characters can be nasty, disgusting, violent, hysterically cruel, and passionately consumed.
    CT Jones, Rolling Stone, 8 Aug. 2026
Adjective
  • Armed with an arsenal of tools – from DIY inventions to GPS trackers to drones – Daniel scours the turbulent Vistula River on an all-consuming search, desperate for answers.
    Leo Barraclough, Variety, 12 Aug. 2026
  • But the fund, overwhelmingly comprised of equities, saw a turbulent first six months of the year.
    Chloe Taylor, CNBC, 12 Aug. 2026
Adjective
  • Trump filed the lawsuit in December seeking $10 billion in damages from the BBC, accusing it of defamation as well as deceptive and unfair trade practices.
    ABC News, ABC News, 16 Aug. 2026
  • That seems rather unfair on those who operated well under their PSR limit, and a concession offered by the EFL arrives in the form of a transitional ‘allowable headroom injection’.
    Chris Weatherspoon, New York Times, 14 Aug. 2026
Adjective
  • Climate Pledge Arena prohibits abusive or obscene language and says violators may be ejected.
    Jackson Thompson OutKick, FOXNews.com, 30 July 2026
  • These stories were reprinted in Scottish and English botanical texts, and Henrietta would have known about the obscene ideas connected with the mushroom.
    Leah Hudson, Popular Science, 9 July 2026
Adjective
  • America’s political landscape has become a stinking mess.
    Mary Ellen Klas, Boston Herald, 1 June 2026
  • Not the good, high-altitude ozone that shields us from dangerous UV light, but bad ozone, hovering right above ground level — stinking, brownish, grayish photochemical smog.
    Patt Morrison, Los Angeles Times, 26 Mar. 2026
Adjective
  • Few things at airports irritate customers like filthy toilets or water on the restroom floor.
    Miami Herald, Miami Herald, 8 Aug. 2026
  • His greatest series let people see a character who has revealed the filthiest, most shameful parts of themselves, and imagine them as a mirror.
    CT Jones, Rolling Stone, 8 Aug. 2026
Verb
  • Satisfy your lasagna craving without dirtying up a pile of dishes.
    Kimberly Holland, Southern Living, 9 July 2026
  • The zipper shoe compartment keeps your shoes from dirtying up your clothing, and the massive interior can hold many outfits for your weekend getaway.
    Olivia Dubyak, Travel + Leisure, 9 Mar. 2026
Verb
  • The only appropriate response to the industry’s rush to build costly, polluting gas plants at the sites of data centers is a pause in development and enactment of new policy guardrails, designed in close consultation with affected communities.
    John Kostyack, Forbes.com, 12 Aug. 2026
  • This large mass will translate into higher quantities of polluting propellant needed to loft these systems off Earth and a much larger amount of metals vaporizing in Earth's atmosphere during reentry.
    Tereza Pultarova, Space.com, 11 Aug. 2026

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Cite this Entry

“Foul.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/foul. Accessed 19 Aug. 2026.

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