muck up

verb

To ruin unintentionally.

“The terrorists have really mucked up our holiday plans.”

Meanings

verbmuck up (third-person singular simple present mucks up, present participle mucking up, simple past and past participle mucked up)

present singular third person mucks up · participle present mucking up · participle past mucked up · past mucked up

  1. informalintransitivetransitiveTo ruin unintentionally.

    The terrorists have really mucked up our holiday plans.

    3 more examples

    That’s why they’re called the Founders? Yes, because it will be their job to repair a world that millennials have mucked up beyond repair.

    2015 December 2, “The Founders, the Plurals, iGen or ReGen – what should we call the post-millennials?”, in The Guardian, →ISSN

    “Looking at our season so far, we have to be honest and admit that we mucked it up ourselves,” Özil told the German website spox.com. “We did not play to our potential in the games against the so-called smaller teams. You immediately get punished for that in the Premier League.

    2016 March 31, Reuters, quoting Mesut Özil, “Mesut Özil: Arsenal ‘mucked it up ourselves’ as trophy hopes recede”, in The Guardian, →ISSN

    He said that this was simply a “historical fact” and that he could “see no reason why every other country in the world should be prevented from feeling pride in itself because the Germans mucked up twice in a century”.

    2023 May 17, Adam Robertson, quoting Douglas Murray, “Author sparks backlash with 'Germany mucked up twice' comment”, in The National

    Synonyms: mess up, blow it, bobble, boob, crap up, miscue, drop a bollock, drop the ball

  2. AustraliainformalintransitiveTo clown around; to have fun, often at the expense of others.

    It's the last day of school and everyone is mucking up.

    Synonyms: muck about, muck around, fuck about, fuck around

Synonyms & antonyms

verbTo clown around; to have fun, often at the expense of others.

More synonyms by meaning

verbsoil with mud, muck, or mire

Synonym sets from Open English WordNet, CC BY 4.0.

Cite this entry
APA

muck up. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/muck%20up

MLA

“muck up.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/muck%20up. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “muck up,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/muck%20up.

Source: muck up on Wiktionary, CC BY-SA 4.0.