Hilchos Shmiras Haloshon
                Reprinted from Guard Your Tongue with permission from Rabbi Pliskin

Chapter Four Halachah  # 12: Faulty Character Traits:

You are forbidden to say about another person that he has faulty character traits.  This applies both to instances when you are referring to a particular incident (for example, he became angry or acted conceitedly) and to instances when you give a general judgment about someone (for example, he's always quick to anger or is arrogant).  The prohibition applies even if the description is accurate and well-known.

It is very likely that the person is unaware of the seriousness of lacking the particular virtue.  The proper procedure would be to explain the gravity of the negative trait and advise him on ways of improving himself.  In this way you will fulfill the mitzvah of delivering reproof, and you will render the person a great service.

Asher is brilliant and performs many charitable deeds.  In fact, he is so perfect that he suffers from an inflated ego, and at times is very obnoxious.  This annoys Yonah intensely.  Beware, Yonah!  Do not tell others that Asher is a baal gaivoh (conceited).

"There he goes showing off again."

Mr. Bernstein is a miser.  He derives an enormous income from a lucrative business.  Observing the size of his donations to the Yeshiva, however, would give the impression that he is a pauper.  It is forbidden to speak about this fault, even if it is well-known.

"He has very bad midos (traits).

Mrs. Kramer is the jealous type.  She passionately desires to acquire whatever her neighbors own.  She is never satisfied merely with what Hashem Yisborach has bestowed upon her.  Mrs. Gold has tried to correct Mrs. Kramer, but to no avail.  Mrs. Kramer's attitude is truly improper, but Mrs. Gold is nonetheless forbidden to tell this to her friends.