run-in
Americannoun
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a quarrel; argument.
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Printing. matter that is added to a text, especially without indenting for a new paragraph.
adjective
verb
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to run (an engine) gently, usually for a specified period when it is new, in order that the running surfaces may become polished
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(tr) to insert or include
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(intr) (of an aircraft) to approach a point or target
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informal (tr) to take into custody; arrest
he was run in for assault
noun
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informal an argument or quarrel
he had a run-in with the boss yesterday
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an approach to the end of an event, etc
the run-in to the championship
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printing matter inserted in an existing paragraph
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Insert or include something extra, as in Can you run this map in with the text? [Early 1800s]
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Also, run on . In printing, make a solid body of text without a paragraph or other break, as in The quotation should be run in rather than set as a paragraph .
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Also, run someone in . Take someone into custody, as in The police were going to run him in, but he got away . [ Slang ; mid-1800s]
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Visit someone briefly, as in If I have time, I'll run in to see Aunt Mary . [Second half of 1800s]
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Break something or someone in, as in Let's run in the new model on a short flight . [Early 1900s] Also see run into .
Etymology
Origin of run-in
First recorded in 1900–05; noun, adj. use of verb phrase run in
Explanation
A run-in is a confrontation or an argument. Peaceful protests go more smoothly when protestors avoid run-ins with the police. If you get in a fight with your brother about how he never loads the dishwasher, you can call that a run-in. A more serious kind of run-in might be a shoplifter's run-in with a store security guard or a basketball player's angry run-in with a referee that gets him benched for the rest of the season. Before 1905, run-in meant an instance of actually running somewhere.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Saka has been carrying the issue for some time, and while there was concern behind the scenes at Arsenal, they deemed the forward fit enough to start regularly during their triumphant title run-in.
From BBC • Jun. 20, 2026
The Arsenal attacker missed part of the domestic season climax through a muscle injury, though he did return in time for the club's run-in as they won the Premier League title.
From BBC • Jun. 9, 2026
I figured a quarter-million miles was an outside chance, but my run-in with Tightsqueeze McHalfmill has given me confidence.
From Barron's • May 29, 2026
Sadly, confinement isn’t the worst thing that can happen to a capybara who has a run-in with a human.
From Slate • May 27, 2026
“I was with the Twenty-fourth Transportation Battalion, but I put in for a transfer ’cause I had a run-in with my commanding officer.”
From "Fallen Angels" by Walter Dean Myers
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.