To do something incorrectly or make a mistake that causes a problem.
I really messed up my presentation by forgetting my notes.
A: Did you finish the report? B: I tried, but I messed up the numbers and have to start over.
Honestly, I messed up my first driving test because I was too nervous.
Common mistake
✗I really messed it.
✓I really messed it up.
'Mess up' is separable but you can't drop 'up' — bare 'mess it' isn't English here.
Tell it apart
I messed up the recipe.
did it wrong
I messed up the kitchen.
made it untidy
You can use 'mess up' when you do something wrong, especially by accident.'Mess up' is about making mistakes, while 'fix' or 'sort out' are about solving problems.
To make something disorganized or dirty; to make a place or thing messy.
The kids messed up the living room with their toys.
A: Who messed up the kitchen? B: Sorry, I was baking and things got a bit out of hand.
When I share a room with my brother, he always messes up my side and it drives me crazy.
Common mistake
✗Don't mess up with my desk.
✓Don't mess up my desk.
'Mess up' + the place (no 'with'). ('Mess with' = interfere — a different meaning.)
Tell it apart
You've messed up the room.
made it untidy
You've tidied up the room.
put it in order
Use 'mess up' when talking about making a place or thing messy, not just playing or wasting time.'Mess up' means to make untidy, while 'clean up' means to make tidy.
To cause someone emotional or psychological harm, distress, or long-term difficulties, often as a result of a traumatic or negative experience.
The constant criticism from her parents really messed her up as a teenager.
A: Why is Tom so withdrawn these days? B: I think losing his job really messed him up.
Some experts argue that exposure to violence at a young age can seriously mess children up, leading to long-term psychological issues.
Common mistake
✗The accident messed up him for years.
✓The accident messed him up for years.
With a pronoun, the object goes in the middle: 'messed him up'.
Tell it apart
Losing his dad young really messed him up.
damaged him emotionally
He messed up the presentation.
did it badly
Used informally to describe someone who is deeply affected or damaged emotionally, often by a difficult experience. Not appropriate in formal writing; use 'traumatize' or 'cause psychological harm' in academic contexts.Unlike the B1 senses, which refer to making a mistake or making something untidy, this sense is figurative and refers to causing emotional or psychological harm to a person.