As long you don’t mention the name and the reader won’t be able to figure it out, this is permissible.

sheikh, if someone misbehaves with me or mistreats me and then I write in my diary that this type of behavior upsets people,it is not good and alike without mentioning the name of that person or the exact incident happened with me,is it considered backbiting and sin or not?

Backbiting | March 9, 2017 5:51 am
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If person ‘A’ has asked person ‘B’ not to inform person ‘C’ about an issue but the person ‘C’ is asking to person ‘B’about the same issue , what should person ‘B’ say to person ‘C’ ? If he says something else would it be considered a lie?
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You know if someone is backbiting to you and your just listening .Does that make you a backbiter aswell?and you should avoid sitting with them kind of people or what?Sheikh please give me advice.