Which sin is greater: backbiting (gheebah) or tale-bearing (nameemah), and what is their expiation?

Backbiting (Gheebah) and slander (Nameemah) are two grave sins, the prohibition of which is mentioned in the Qur’an and Sunnah. Backbiting is your mentioning of your brother with what he dislikes, and slander is spreading tales among people to cause discord. The expiation for both is to hasten with sincere repentance to Allah Almighty and to seek forgiveness from those whose rights have been violated and those who have been wronged. However, if one fears a greater harm from seeking forgiveness, then he must supplicate for them, mention their good qualities, and increase in righteous deeds.