Buhtān is to spread malicious lies about someone. It’s a sin worse than Ghībah, which is to spread truthful information that hurts somebody.
Slander 73. Rasûlullâh sallallâhu ‘alayhi wa sallam said: "Allah will make the person who accuses his fellow Muslim of something that is not to be found in him, stay in the place where the blood and pus of the dwellers of hell gathers. He will remain in this place until he gives up this accusation and makes taubah."
The Prophet said, “Slander is worse than adultery.” He was then asked how that can be worse than adultery, to which he replied, “If a person commits adultery, he can be forgiven by God if he repents. However, a slanderer will not be forgiven until he is forgiven by the person about whom he was talking (badly).” (Bayhaqi) The classical commentator Qatadah described the first verse of this chapter as being about those who torture others with their tongue and eyes (with cruel stares). He also said, “The worst of God’s servnts are those who speak ill of another in order to cause hatred between friends, and also those who constantly find faults with other people.” (Maʿariful Qurʾān)
also: yaghtab 49:12
Does H-M-Z mean the same thing?