Source: The Great Interpretation of Dreams (Ibn Sirin)
Eating clay in a dream indicates backbiting, slander, consuming the deceased's money, or unlawful money.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Eating clay indicates illness or worry.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Eating clay is interpreted as worry and illness.