Laws of Rechilus / 3: 2-4 (90)

2. If Levi told Shimon that Reuven spoke badly about him, Shimon is forbidden to tell so to Reuven, as this would be rechilus about Levi. Even when not mentioning Levi’s name, if Reuven can figure out who he’s referring to, it is forbidden.

3. It is forbidden to speak rechilus even to others, as it is the way of the world, that in due cause it will reach the ears of the person spoken about.

4. The laws of speaking rechilus for a constructive purpose are explained above, laws of lashon hara / 10: F.