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1. verb To speak negatively or unflatteringly about someone or something. Why are you always bad-mouthing Tiffany? You don't even know her that well!
2. noun One who says negative or unflattering things about someone or something. He's a real bad-mouth, so don't listen to anything he says about me!

bad-mouth someone or something

to say negative things about someone or something. Mr. Smith was always bad-mouthing Mrs. Smith. They just didn't get along. John bad-mouths his car constantly because it is too small for him.

bad mouth

Disparage or criticize unduly, malign, as in Why do you constantly bad mouth your colleagues? This term is believed to be of African origin, where the phrase bad mouth signifies a curse or evil spell. [1930s]
See also: bad, mouth


1. tv. to speak ill of someone or something. (see also dirty mouth, poor-mouth.) I wish you would stop bad-mouthing my car.
2. n. someone who speaks ill of someone or something. Harry is such a bad-mouth!
References in periodicals archive ?
The first thing any person associated with Royalty should be made aware of is never, and I mean never, bad-mouth anyone.
Don't bad-mouth her - tell her that addiction is an illness and stress how much her mum loved her and how proud she will be to see her grow up and not repeat her mum's fate.
Randal is happy to bad-mouth everything and everyone that moves, but Dante is about to get married and head off for a better life in Florida.
I try very hard not to bad-mouth their dad in front of them, even though I think it.
We agreed to be civilised about access and not to fight in front of the kids or bad-mouth each other.
They're the ones who flirt with your partner, bad-mouth you behind your back, borrow DVDs that are never returned and would cancel a night out with you if there was a better offer from a potential mate.
But not the grudging Scottish National Party, who seem to think their only reason for existence is to bad-mouth and belittle instead of backing worthwhile initiatives.
Despite these damning findings by fellow MPs, Vaz still twists and turns and bad-mouths parliamentary commissioner for standards Elizabeth Filkin.