Is it still backbiting if what I say is true?

The Prophet's definition

The Prophet ﷺ asked his companions whether they knew what backbiting is. He said it is talking about your brother in a way he would not like. When someone asked, "What if what I say is actually true?", he replied: if what you say is true, you have backbitten him, and if it is not true, you have slandered him (Sahih Muslim 2589). So truth is not a defence. It is exactly what makes it backbiting.

Why the Quran takes it so seriously

Allah compares it to something nobody would choose to do:

The picture is that the person is absent and cannot defend himself, just like a dead body. It is easy to slip into because it feels like "just talking", for example about a colleague's habits or a relative's marriage. The wider Quranic teaching is summarised elsewhere. See What does the Quran say about backbiting?

When is it allowed?

Scholars list a few situations where saying something negative about a person is not forbidden, because there is a real need:

• Seeking justice: telling a person with authority, such as the police, a manager or a court, about a wrong that was done to you. Allah says He does not like negative things to be said openly, except by someone who has been wronged (Quran 4:148).
• Asking for a ruling: Hind bint 'Utbah told the Prophet ﷺ that her husband Abu Sufyan was stingy and did not give enough for her and her children, and asked whether she could take from his property. He told her to take what is reasonable and sufficient (Sahih al-Bukhari 5364).
• Warning others about real harm: for example, about a scammer or an abuser, keeping to the facts and saying only what is needed.
• Getting help to stop a wrong: speaking to someone who can actually fix the problem.

The test is your purpose. If you are trying to solve a problem or protect people, that's different from venting, entertaining a group or making someone look bad. Posting about people online follows the same rules. See Is it backbiting to complain about someone online?

What should I do instead?

• Ask yourself first: would they dislike this being said? Is there a real need? Am I telling someone who can help?
• Speak to the person kindly if you have a real concern, rather than about them.
• Change the subject or leave when others start. The Prophet ﷺ said that whoever protects his brother's honour, Allah will protect his face from the Fire on the Day of Resurrection (Jami at-Tirmidhi 1931).
• Say good or stay silent, as the Prophet ﷺ taught (Sahih al-Bukhari 6018). If you slip, repent and, where it causes no harm, ask the person's pardon.

Group chats are a common trap for gossip. See Should I leave a group chat full of gossip?