Dictionary.com
Thesaurus.com
Jump To:
  • run-in
    run-in
    noun
    a quarrel; argument.
  • run in
    run in
    verb
    to run (an engine) gently, usually for a specified period when it is new, in order that the running surfaces may become polished
Synonyms

run-in

American  
[ruhn-in] / ˈrʌnˌɪn /

noun

  1. a quarrel; argument.

  2. Printing. matter that is added to a text, especially without indenting for a new paragraph.


adjective

  1. Printing. added to a text without indenting.

run in British  

verb

  1. to run (an engine) gently, usually for a specified period when it is new, in order that the running surfaces may become polished

  2. (tr) to insert or include

  3. (intr) (of an aircraft) to approach a point or target

  4. informal (tr) to take into custody; arrest

    he was run in for assault

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noun

  1. informal an argument or quarrel

    he had a run-in with the boss yesterday

  2. an approach to the end of an event, etc

    the run-in to the championship

  3. printing matter inserted in an existing paragraph

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
run in Idioms  
  1. Insert or include something extra, as in Can you run this map in with the text? [Early 1800s]

  2. 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 .

  3. 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]

  4. Visit someone briefly, as in If I have time, I'll run in to see Aunt Mary . [Second half of 1800s]

  5. 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.

Keep Reading on Vocabulary.com

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.

See Examples For:

In his 2025 memoir, “Truly,” Richie recounted a chance run-in with the comedian George Burns at the Polo Lounge.

From The Wall Street Journal ● Sep. 16, 2026

Daniel's easy run-in on the wing got Wigan going after the break before Field raced in from Farrell's offload to continue the rout.

From BBC ● Sep. 11, 2026

Trump and Cohen broke the ice during a “brief yet significant” run-in at one of Trump’s golf clubs last summer, the New York Times reported.

From Slate ● Aug. 24, 2026

After a rough start, including a run-in with an irritating policeman, she lands at the home of a baker, Osono, who gives her a place to stay in exchange for labor and her delivery services.

From Salon ● Jul. 30, 2026

I wouldn't be able to sneak my way out of a run-in with him—not after our last encounter.

From "The Sky at Our Feet" by Nadia Hashimi

Michael Harris II shouldn’t have been 90 feet away from scoring the go-ahead run in the first place.

From Los Angeles Times ● Oct. 5, 2026

Google has launched a satellite to find out whether data centers can run in space.

From The Wall Street Journal ● Oct. 1, 2026

Although the deal “wasn’t received as a home run in the market,” Meeks said it’s a solid move for a company looking to pick up market share in the broader world of chips.

From MarketWatch ● Sep. 29, 2026

The Quebec-born star recently launched a much-publicised return to the stage with a 26-show run in the French capital, with 16 set for September and October and a further 10 planned for May 2027.

From Barron's ● Sep. 28, 2026

"All right, here we are. I'm going to run in and drop off that tray of food. Don't open the door to anyone, got it?"

From "The Sky at Our Feet" by Nadia Hashimi

Vocabulary.com logo
by dictionary.com

Join 14,000,000 vocabulary learners

Start learning new words today on VocabTrainer.
You'll remember them forever.

Start training