English

Verb

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

1. (transitive) To ruin unintentionally.

   The terrorists have really mucked up our holiday plans.

2. (intransitive) To clown around; to have fun, often at the expense of others.

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

Derived terms

• muck-up day