- Slang. to speak critically and often disloyally of; disparage: Why do you bad-mouth your family so much?
Origin of bad-mouth
- (tr) slang to speak unfavourably about
Word Origin and History for bad mouth
"abuse someone verbally," 1941, probably ultimately from noun phrase bad mouth (1835), in Black English, "a curse, spell," translating an idiom found in African and West Indian languages. Related: Bad-mouthed; bad-mouthing.
Idioms and Phrases with 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]