1 B1 idiomatic informal
To do something badly or fail at it.
"I completely mucked up my driving test — I stalled three times."
separable
muck up
B1 informal separable transitive
To do something badly, spoil it, or make it dirty.
In plain English
To ruin or make a mess of something.
What does "muck up" mean?
3 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B1 idiomatic informal
To spoil or ruin a plan, event, or situation.
"The rain completely mucked up our plans for a barbecue."
separable
3 B1 informal
To make something physically dirty or messy.
"Don't muck up your school uniform before the photo!"
separable
Literal vs figurative
Words literally mean
To cover something with muck (dirt) — the figurative sense of ruining is a natural extension.
Actually means
To ruin or make a mess of something.
Usage tip
Common in British English. Milder than 'screw up.' Can refer to spoiling a plan, failing a task, or literally making something dirty. The object usually goes between 'muck' and 'up' or after the full phrase.
Words that pair with "muck up"
Natural word combinations native speakers use most often.
exam interview plan opportunity performance chance
How to conjugate "muck up"
The five tense forms you'll use most often.
Base
muck up
I/you/we/they
3rd person
mucks up
he/she/it
Past simple
mucked up
yesterday
Past participle
mucked up
have + pp
-ing form
mucking up
continuous
Hear "muck up" in the wild
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Other ways to say "muck up"
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