- to say something bad about something
- to malign, criticize or disparage something unduly
- say unpleasant things about somebody or something, especially in order to spoil other people's opinions of them
- The social parties in this area are just meant for old ladies to gather around and bad-mouth everyone who did not show up. I would never go for one.
- I am not one to bad-mouth anybody for their appearance.
- In her school, the kids badmouth their teachers. I would be apprehensive to put my child there.
- Bad mouthing people is the worst use of your time possible. Please try to do something that is more worthwhile.
- This aspect of her bad mouthing everything that happens has made her very unpopular.
- I do not like to speak with people who enjoy bad mouthing.
- You should not badmouth your friends.
- I wonder, why Jenny always bad-mouth your acquaintances?
The origin of this phrase is among the ones that literally mean what they say. "Bad mouth" can be looked as "bad things coming from the mouth". This could include abusing or saying negative things about something, someone or an incident even. The phrase is speculated to come from Africa from the 1930's where bad mouthing meant to put an evil spell on someone, usually innocent.