According to authentic Prophetic teachings and classical Islamic scholarship, Slander (البهتان - al-Buhtan) is the grave sin of fabricating a falsehood against a person. A definitive hadith recorded by Imam Muslim clearly distinguishes it from backbiting (*ghibah*): while backbiting is saying something negative but true behind someone's back, slander is concocting a lie against them. The Quran condemns this act in the strongest terms, describing it as a "monstrous slander" (24:16) and a "manifest sin" (4:112) that burdens the perpetrator with immense guilt. Classical commentators like Ibn Kathir and Al-Qurtubi explain that this sin not only harms an individual's reputation but also attacks the fabric of social trust and incurs severe divine punishment. The historical slander against Mary, the mother of Jesus (4:156), is cited in the Quran as an act of disbelief, highlighting the theological severity of such false accusations. This comprehensive understanding establishes slander as one of the most destructive sins of the tongue, requiring sincere repentance and, in certain cases, legal restitution.