1 B1 idiomatic informal
To make a serious error or ruin something through incompetence or carelessness.
"I completely effed up the job interview by arriving late and forgetting my CV."
separable
eff up
B1 informal separable transitive/intransitive
A euphemism for 'f*** up' — to make a serious mistake or ruin something.
In plain English
A way to say (without using the full swear word) that someone made a big mistake or badly messed something up.
What does "eff up" mean?
One main meaning — here's how to use it.
Usage tip
Used in print, broadcast media, and polite conversation as a substitute for the more explicit profanity. Slightly softer than the full form but still considered rude in many contexts. Common in British English. Can be used transitively ('She effed up the presentation') or intransitively ('He really effed up').
Words that pair with "eff up"
Natural word combinations native speakers use most often.
really completely totally badly everything it
How to conjugate "eff up"
The five tense forms you'll use most often.
Base
eff up
I/you/we/they
3rd person
effs up
he/she/it
Past simple
effed up
yesterday
Past participle
effed up
have + pp
-ing form
effing up
continuous
Hear "eff up" in the wild
Listen to native speakers using "eff up" in real YouTube videos — click a clip to watch it on Looplines.
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