badmouths
bad-mouths
verb
Speaks critically or disparagingly about someone or something, often behind their back.
"He always badmouths his ex-boss."
Thesaurus
Synonyms: malign, drag through the mud, traduce
bad-mouths
Speaks critically or disparagingly about someone or something, often behind their back.
"He always badmouths his ex-boss."
Synonyms: malign, drag through the mud, traduce