Also found in: Dictionary, Thesaurus.

fall (a)foul

To become disliked or to come in conflict with due to one's actions, often resulting in further trouble or conflict. Used in the phrase "fall (a)foul of (someone or something)." Since you're new here, be careful not to fall afoul of Bill—he'll keep you off of every case if he's mad at you. I fell foul of the committee, and now, I'm not sure how to improve my reputation.
See also: fall

fall (a)foul of (someone or something)

1. To become disliked or to come in conflict with someone or something due to one's actions, often resulting in further trouble or conflict. Since you're new here, be careful not to fall afoul of Bill—he'll keep you off of every case if he's mad at you. I fell foul of the committee, and now I'm not sure how to improve my reputation. Ted fell afoul of the law when he was still a kid, and he's been in and out of jail ever since.
2. nautical, obsolete To strike the side of another ship. The two vessels, pitched and tossed as they were by the storm, fell foul of one another and sank into the cold Atlantic ocean.
See also: fall, of

run afoul of (someone or something)

1. nautical To collide or become entangled with something. The schooner lost control and ran afoul of the lead boat. The small powerboat ran afoul of the seaweed and was completely immobilized.
2. To be in severe disagreement, trouble, or difficulty with someone or something; to be at odds with someone or something, especially due to disobeying rules or laws. Always look into the laws of any place you visit, or you may end up unwittingly running afoul of the local police. Ms. Banks has run afoul of this university for the last time. She is no longer welcome here!
See also: afoul, of, run
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.

run afoul of

Also, run foul of. Come into conflict with, as in If you keep parking illegally you'll run afoul of the police. This expression originated in the late 1600s, when it was applied to a vessel colliding or becoming entangled with another vessel, but at the same time it was transferred to non-nautical usage. Both senses remain current.
See also: afoul, of, run
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
See also:
References in periodicals archive ?
In another recent, well-publicized case, Oregon's Rose Bowl opponent, Wisconsin, ran afoul of the rule last year when receiver Nick Toon acknowledged in a television interview that quarterback Russell Wilson had visited campus while researching a transfer destination.
A serious development has been the growing refusal of international banks to conduct Cuban business in dollars, for fear of running afoul of US regulators, he said.
In June, the national church's synod voted down a plan to let local churches decide for themselves whether to bless same-sex marriages while also saying that same-sex blessings do not run afoul of core Anglican doctrine.
The investigation will allow the Commission to assess whether such support falls afoul of EU State Aid rules.
Three days later--after running afoul of a berserk robot, engaging in hand-to-hand combat with Nagi's pet tiger, and being forced to model a pretty sailor dress-the Yakuza are starting to look like a pretty good deal.
Bush had popular support for many of his programs before running afoul of public sentiment, so too did Lyndon Johnson.
Meanwhile back in the United States, sprinters Justin Gatlin and Marion Jones, who have garnered eight Olympic medals between them, both ran afoul of the U.S.
No, he didn't run afoul of the USA PATRIOT Act, which infamously allows the government to subpoena library records.
Carter, in which Governors State University's (Ill.) student newspaper, The Innovator, ran afoul of the administration by publishing some scathing reports on administrators.
Not only do companies risk incurring interest and penalties for compliance errors, but if their processes lack the required transparency in respect of every facet of the compliance function, management runs the risk of running afoul the rigorous requirements of the Sarbanes-Oxley Act.
In discussing the disrupted households in which servants sometimes fell afoul of their masters leading to the death of one or the other or both, for example, the real focus is on disorder in the community for "[a]fter all, order in the household reflected on wider society.
Even well-thought-out programs for new technology deployments can run afoul of organizational resistance, writes Longview Technologies CFO Dave Murray in our cover story on maximizing the use of technology.
Pizer, who is representing Benitez, says doctors who specialize in certain forms of treatment but refuse to provide that treatment to all patients risk running afoul of state and federal laws.
Moreover, archaeology and DNA research sometimes runs afoul of American Indian activists who have their own vision of pre-Columban society.
Gallagher, vice president of the Metals and Advanced Manufacturing Division of MSA, participants pledge that this information is accurate and verifiable and risk running afoul of Sarbanes-Oxley requirements if it is not.