mess with someone/something

mess with (someone or something)

1. To change, fiddle, or play with something, often without permission to do so. My tools are not toys—please do not mess with them. Hey, don't mess with the thermostat—it needs to stay at 65 degrees.
2. To clash with someone or something. That group of boys is dangerous—don't mess with them.
3. To tease or mock someone. Sarah's a very sensitive kid, so don't mess with her.
4. To confuse or puzzle someone. One minute he's flirting with me, and the next, he's completely disinterested. His mixed signals are totally messing with my head!
See also: mess
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

mess with someone/something

and monkey with someone/something
in. to bother or interfere with someone or something. Don’t mess with me unless you want trouble. Don’t monkey with the TV. It’s out of kilter.
See also: mess, someone, something
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
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