Backbiting, backstabbing, or tale-bearing is to slander someone in their absence — to bite them behind their back.
Backbiting is defined by a Hadeeth narrated from the Prophet Muhammad (SAWA) as : Mentioning your brother by a matter which he dislikes to be mentioned. A person asked the Prophet: Even if I mention a real matter in him? The Prophet replied: If you mention a real matter which does not like to be mentioned, yoy have committed backbiting him, and if you mention a matter which does not exist in him, you have put allegation on him.
Allegation is obviously more dangerous major sin.
Backbiting is a bad habit in any way. Backbiting a believer is a major sin. Backbiting any one is a bad act unless you want to warn people from a possible harm from a person.
It is not good to talk to people about someone who did wrong to you, unless you have no other way to stop the wrong but seeking help from people by telling them.
If your telling people will not change the situation, it can be also a type of back-biting unless this person who wronged you is doing it openly and is insisting on doing the wrong to you. Allah SWT says : Allah does not like the wrong should be uttered in public but by him who has been wronged)(Sura 4, Verse 148). If the
person who did the wrong insisted on doing the wrong on you and there
is no way to stop his wrong acts against you but to talk to others who
might help, then it will be allowed.
as salam alaikum
if a person is openly a sinner, unjust or oppress other people, he is considered a wrongdoer (zalim).
If a person consciously, willingly and openly fights the truth, while knowing that it is the truth, it is disbelief (kufr) or apostasy (irtidad).
If a person reveals what a Muslim person hide from his sins, it is called backbiting (ghibah).
So the basic difference is that declaration of zulm, kufr and apostasy are related to open attitudes and behaviors while backbiting is related to something that a Muslim person wish to conceal about himself.
As far as the Khawarij, their enmity against Ali, peace be upon him, has been seen as an aversion for the truth even if it is not improbable that among their ranks were also unaware people misled by their leaders.
With prayers for your success.
There are many narrations both in Shia and Sunni books stating that the person who back bites a Momin will lose part of his good deeds to the victim, and in case that his good deeds are less, part of the bad deeds of the victim will be transferred to him.
Backbiting is a major sit which mentioned in Quran as eating the flesh of your dead brother. (And do not backbite each other, does any one from you like eating the flesh of his dead brother, then you will hate him).
Backbiting is (Mentioning any Momin with anything which he / she does not like to be mentioned). If it was a true, then it s backbiting, but it was untrue then iy will be allegation which more dangerous.
Repenting from backbiting is Must otherwise it will lead to hellfire.
As it is a sin concerning others, we must seek pardon from them and request them to sincerely forgive us. If this is not possible either if the person is no more alive or he is not contactable a all or it might be more harmful to inform him, then we need to pray for him and gift him good deeds which will make him in the Day of Judgment forgive us.
The first step of Isteghfar is to resolve never to commit the sin again. Then you have to, in the case of backbiting, seek out those you may have talked ill of and ask for forgiveness. Thereafter, one has to seek forgiveness from Allah. Should all these steps be taken in all earnest and sincerity, then Allah is the Most Merciful and All forgiving.