bad-mouth

[bad-mouth or, sometimes, -mouth] /ˈbædˌmaʊθ or, sometimes, -ˌmaʊð/
verb (used with object), bad-mouthed, bad-mouthing.
1.
Slang. to speak critically and often disloyally of; disparage:
Why do you bad-mouth your family so much?
Also, badmouth.
Origin
1935-40; originally a curse, spell (the sense recorded in Gullah); compare Vai (Mande language of Liberia and Sierra Leone) dà nyà mà curse, literally, bad mouth
Related forms
bad-mouther, noun
British Dictionary definitions for bad-mouth

bad-mouth

verb
1.
(transitive) (slang) to speak unfavourably about
Word Origin and History for bad-mouth
v.

"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.

Slang definitions & phrases for bad-mouth

bad-mouth

noun phrase

: If you can't say anything good, at least don't be a bad mouth

verb phrase

To disparage; denigrate: He bad-mouthed everybody (1930s+)