mess with

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Related to mess with: mess around with, worse for wear

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 or something

 and monkey with someone or something
to bother or interfere with someone or something. Come on, don't monkey with my new camera. Don't mess with me unless you want trouble.
See also: mess
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

mess with

Interfere or associate with; also, annoy, bother. For example, Our group won't mess with those street musicians, or I told him not to mess with me or there would be trouble. [Colloquial; c. 1900]
See also: mess
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

mess with

1. To alter something improperly: Don't mess with the arrangement of the chairs—they're all set up for the meeting.
2. To deceive or confuse someone or something: The horrible accident really messed with my head.
See also: mess
The American Heritage® Dictionary of Phrasal Verbs. Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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References in periodicals archive ?
The post "Don't mess with our elections": Hackers warn Iran appeared first on Tahawul Tech.
I felt the author had left me with a bad mess with few or no options.
I have never known a school to make such a mess with litter during their dinner break.The surrounding pavements are a disgraceful mess of paper, food and cans.
Murray: Too many conservatives are too happy to mess with me in ways I don't think they have any right to mess with me.
The Alig allure is probably best summed up by his last boyfriend, a recovering heroin addict who claims, "I was attracted to the was fun being a mess with Michael." The creepy double-edged sword of Party Monster is that it allows you to see how liberating it could have been to be a mess with Michael at the same time as you mutter, "There but for the grace of God," under your breath.