1 B2 idiomatic informal
To ruin or spoil something through error, carelessness, or incompetence.
"I completely loused up the presentation by forgetting half my notes."
separable
louse up
B2 informal separable transitive
To spoil, ruin, or make a mess of something through carelessness or incompetence.
In plain English
You totally ruin something or make a big mistake with it.
What does "louse up" mean?
2 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B2 idiomatic informal
To cause problems that prevent something from succeeding.
"One bad review loused up all the momentum the film had built."
separable
Literal vs figurative
Words literally mean
To infest something with lice, making it filthy and ruined.
Actually means
You totally ruin something or make a big mistake with it.
Usage tip
Primarily American English, and slightly dated compared to 'mess up' or 'screw up.' Still understood by most English speakers. Often used with personal responsibility: 'I really loused that up.'
Words that pair with "louse up"
Natural word combinations native speakers use most often.
plan interview relationship deal chance everything
How to conjugate "louse up"
The five tense forms you'll use most often.
Base
louse up
I/you/we/they
3rd person
louses up
he/she/it
Past simple
loused up
yesterday
Past participle
loused up
have + pp
-ing form
lousing up
continuous
Hear "louse up" in the wild
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