badmouth (someone) to (someone else)

Translations
плохо говорить о (ком-то) (кому-то другому)
He badmouthed his boss to his coworkers.
Он плохо говорил о своем начальнике своим коллегам.
Definitions
To speak negatively or disparagingly about someone to another person, often with the intention of damaging that person's reputation or relationships.
Words
badmouth

verb
очернять
someone

pronoun
кого нибудь
to

preposition
кому
someone

pronoun
кого нибудь
else

adverb
другому