mess with

annoy or cause trouble for someone or something

B2

What does "mess with sb/sth" mean?

To 'mess with' something or someone means either to interfere with it in a way that causes problems, or to provoke and challenge a person in a way that could lead to trouble. Both senses share the idea of getting involved in something you probably shouldn't. When used with a person, it often carries an implicit warning — suggesting the person is dangerous or not worth provoking. A closely related and very common use is 'mess with someone's head or mind', which means to confuse or manipulate someone psychologically. The expression is strongly informal and is especially common in American English, appearing frequently in warnings, threats, and casual speech rather than in formal writing.

Examples

How to use it

don't mess with + person/thing

The negative imperative is one of the most common patterns, typically used as a warning to stay away from someone or something.

Don't mess with the router — I finally got the Wi-Fi working properly.

mess with + person

Used to describe provoking, antagonising, or challenging someone, often implying it was a bad idea.

He messed with the wrong guy and came off much worse for it.

mess with + thing

Used to describe interfering with or tampering with an object, system, or plan.

Someone messed with the presentation file and now half the slides are missing.

mess with + pronoun (me / him / it / them)

Pronoun objects are especially natural in spoken English, particularly in warnings or expressions of frustration.

I wouldn't mess with her if I were you — she's a former boxing champion.

mess with + someone's head/mind

This fixed collocation means to confuse or psychologically manipulate someone.

The constant rumours were really messing with her head.

Common Collocations

mess with someone's headmess with the wrong personmess with someone's stuffmess with the settingsmess with someone's feelingsmess with someone's mind

Common Mistakes

Trying to separate the verb and particle

'Mess with' is inseparable — the object must always follow 'with', never appear between 'mess' and 'with'. This applies to all objects, including pronouns.

✗ Don't mess me with. / She messed the settings with.
✓ Don't mess with me. / She messed with the settings.
Confusing 'mess with' and 'mess up'

'Mess up' means to ruin something or make a mistake, while 'mess with' means to interfere or provoke — the outcome isn't necessarily ruined.

✗ He messed with the whole project by forgetting to save.
✓ He messed up the whole project by forgetting to save.
Using passive voice

Passive constructions sound unnatural with 'mess with' in most contexts. It's almost always used in the active voice.

✗ The settings were messed with by someone.
✓ Someone messed with the settings.

Usage

This is an informal, mainly spoken expression common in American English. It often appears in warnings or threats ('You don't want to mess with him'), so be careful about the context and tone when using it.

Frequently Asked Questions

Is 'mess with' mainly American English?

Yes, it's most strongly associated with American English and is particularly common in American speech and media. That said, it's widely understood in other varieties of English too, and you'll encounter it in British and Australian informal speech as well.

Does 'mess with' always sound threatening or aggressive?

Not always. When used with a person it often carries a warning tone — 'don't mess with her' implies danger or confrontation. But when used with objects or settings, it's more neutral and just means interfering with something. The context and tone of the sentence make the difference.

Can 'mess with' mean the same as 'mess around'?

'Mess around' and 'mess with' are related but different. 'Mess around' often means to waste time or behave foolishly, and it's frequently used without an object. 'Mess with' always takes an object — a specific person or thing you're interfering with or provoking.

Is it okay to use 'mess with' in formal writing?

No — 'mess with' is strongly informal and would sound out of place in professional or academic writing. In a formal context, you'd use something like 'tamper with', 'interfere with', or 'provoke' instead.

What's the difference between 'mess with someone' and 'mess with someone's head'?

'Mess with someone' broadly means to provoke or antagonise that person. 'Mess with someone's head' (or mind) is a fixed phrase with a more specific meaning: to confuse, manipulate, or psychologically unsettle them. Both are very common, but the 'head/mind' version focuses on the mental or emotional effect.

Ready to practise?

Practise 1,000+ English phrasal verbs with interactive gap-fill exercises.

Start Practising →