Laws of Lashon Hara / 9: 1-2 (70)

1. It is forbidden to speak avak lashon hara (lit. the dust of lashon hara), for instance to make a comment: “It’s amazing how far he’s come”, or “I won’t mention what happened to so-and-so”. So too, it is forbidden to praise one in front of his enemies or to excessively praise someone, as this often leads to negative talk.

2. One should not praise someone in public as this causes at least one of those present to speak disparagingly of him. When the subject is renowned as a learned, righteous person, it is permitted to praise him – even in front of his enemies.