Sefer Chofetz Chaim Chapter 3, halacha 5, note 5, with the footnote

Today we discussed that even in a casual manner if you say something which at first glance might not seem negative but your in trickery intent is to throw in a negative fact bout someone, even if hinted to and said straight out, it is still forbidden. 

I gave an example of two neighbors schmoozing about a new family that moved into town and they were discussing how it is a big family with 7 children and they seem to be a very nice and polite family, simple, moving into a 3 bedroom house. One neighbor just wonders how they can fit any guests but then  says he is excited to meet them and get to know them!  

That line thrown in about guests was a casual remark not meaning to be out right malicious but it might imply that this family is not as hospitable then they outwardly seem. That is lashon hara.

Even to possibly just say they are a simple family of 9 living in a 3 bedroom house would be at least avak lashon hara (rabbinic, dust of lashon hara) because that will imply they aren’t hospitable. Of course as we learned before the permissibility or forbiddance of avak lashon hara depends on one’s tone and intent was it meant to be positive or negative, and how did it come out.

Sefer Chofetz Chaim Perek 2, Halacha 2, Note 2

The answer to Tosfos’ view on apei tlasa is that straight out negative lashon hara is forbidden to be said whether in front of 3 or more people or even to the antagonist’s straight up lashon hara is forbidden, also to listen and accept as true. However the leniency is in a case where the statement could be taken in two ways, positive or negative. The key to the leniency is if you don’t feel embarrassed at all to be willing to say it to his face then you may say it to him or her or even in front of 3 people since it will definitely get back to the person being talked about. However if you feel any embarrassment to say it or if your expressions, voice, physical, etc is of a negative connotation it should not be said.

Chapter 2, Part 2 of Note 1 in Halacha 1 and Halacha 2

Today we finished the first note of the Be’er Mayim Chaim in Chapter 2 of Sefer Chofetz Chaim. The Chofetz Chaim makes it very clear that there is no reason what so ever to allow out right lashon hara to be spoken even if it is in front of three people and it will spread to the one being talked about. It actually could be worse. Only if there is some benefit like in a court case the litigant can tell the judges how he was wronged or a messenger of the court can even tell the judges he was disrespected when on the mission of the court to bring someone in. Otherwise it is absolutely forbidden!

 In Halacha 2 the Chofetz Chaim begins to explain where the concept of “apei tlasa” does apply. Which is when a pareve statement is made that can be taken one of two ways. As long as you connotation and body language does not indicate negativity then one can say this statement in front of at least 3 people because it will spread and get back to the one being talked about so obviously if he said is he is saying it in a positive light because he wouldn’t want the subject to know what he is saying if it was negative. This type of state is in the category of “avak lashon hara”. The example the Chofetz Chaim gives of such a statement is if a person asked a group of people where can I find some good around here and one of them respond there is always a fire brewing down the street at this guy’s house where they always have fish and meat. This can be taken in a positive light to mean he has a big family and is well to do so they can afford, with G-D’s help lavish food, or it can mean they are always ready to serve guests. But it can also be taken negatively that the guy is a glutton and a fresser. So as long as the one who says the statement doesn’t sound negative and sarcastic then he can say it in a group because we can assume he is just trying to be helpful and positive.