ПЕРЕМЫВАТЬ (МЫТЬ) КОСТОЧКИ кому, чьи
- to talk unkindly about someone behind his back, discuss and criticize someone’s behavior in detail: pick (tear) someone to pieces
- gossip about someone
- be dishing the dirt about someone < The phrase originates in the ancient custom of giving a deceased person a second burial. While performing the customary ritual of washing the exhumed remains, i.e. the bones («косточки»), in preparation for reburial, people recalled and spoke of the deceased.