There are many cases that fit into the category of avak rechilus, the dust of rechilus or quasi rechilus, which means you say something which isn’t negative, but the listener might take it negative and therefore it’s forbidden to say. Here are a few examples, please use your head to apply to cases elsewhere:
1. Gary at Todd, how is David doing? Todd says I don’t want to talk about it, or shhhhh, I don’t want to tell you what happened or what’s going to be with him. The point is Todd is obviously hinting to something bad that David is involved with, and Gary might now think up negative thoughts about David which might be or might not be true, but they are negative so it’s avak rechilus, even if the words that Todd said were not negative at all. If Todd had a negative tinge to his voice, then it could be real rechilus especially if Gary is looking for something, has an agenda to know what’s happening with David, but at the very least it is still avak rechilus. The best thing to say is David is fine and moves on with the conversation.
2. If you praise a person in front of someone else, not just his enemy, even loved ones or partners in business, if they will get upset then you can’t praise the person in front of them. For example you praise someone’s partner or spouse in front of their face on how much tzedaka he or she gives, or leant you a big loan, and the like. They might get and think how is just wasting or spending money without calculating, the business will go down the drains or he doesn’t care enough about the family etc. It might lead to arguments or even break ups. This only applies to telling people about big gifts or big loans or the like. This is why the gemara in Erichin 15a says “Do speak praise of your friend because through good it will come to bad.”
3. If you ask a favor from someone and he said I can’t do it. You can’t say back so and so told me you did this favor for him so why can’t you do it for me? The guy might get upset at the one he did the favor to because he told someone else what you did. And even if you don’t tell him that he told you that this guy did a favor for him, you just say I know you’ve done this favor for other people and it’s he knows who must have told him, that us still avak rechilus, because now he will be upset at the person, he originally did the favor to. 4. If you say something that you heard, that could be taken 2 ways. For example, if you tell someone I heard from so and so that you always have a fire on in your kitchen cooking meat and fish all the time. That could mean he’s a glutton and his wife is always cooking for him tons of delicacies to eat or they always have a lot of guests and she cooks up a storm all the time. He might have taken it the wrong way and think so and so was calling him a glutton and feel insulted. We see the severity of this issue from a Yerushalmi in Peah 1:1 with the Pnei Moshe who says that the Angel’s changed what Sarah said when they spoke to Avraham. Instead of saying she laughed and said my husband is old they said that she said I am old. Even though it was the reality and not an insult but it was like avak lashon hara so it was worth lying for this is the severity of avak lashon hara and avak rechilus.
5. The Chofetz Chaim quoting Rabbeinu Yona says this is worse than any other avak rechilus: A person must keep secret a secret his friend confided in him about, even though revealing the secret might not be rechilus but it could cause damage to the person who said the secret and might psychologically disturb him if he finds out the secret was leaked. Also it’s a lack of modesty to reveal a secret and he is just going against the words of the person who entrusted him with that secret.