1 B2 informal
To make hair or clothing untidy and dishevelled.
"The wind completely mussed up her carefully styled hair."
separable
muss up
B2 informal separable transitive
To make hair, clothing, or a tidy space dishevelled and untidy.
In plain English
To make something neat — especially hair — look messy and untidy.
What does "muss up" mean?
2 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B2 informal
To make a tidy space or arrangement untidy.
"Don't muss up my desk — I know exactly where everything is."
separable
Usage tip
Predominantly American English. Most commonly used about hair ('muss up someone's hair') or clothing. Suggests a playful or accidental untidiness rather than serious disorder. British English speakers would more likely say 'mess up.'
Words that pair with "muss up"
Natural word combinations native speakers use most often.
hair clothes outfit room sheets look
How to conjugate "muss up"
The five tense forms you'll use most often.
Base
muss up
I/you/we/they
3rd person
musses up
he/she/it
Past simple
mussed up
yesterday
Past participle
mussed up
have + pp
-ing form
mussing up
continuous
Hear "muss up" in the wild
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