Adam Kasia (Classical Mandaic: ࡀࡃࡀࡌ ࡊࡀࡎࡉࡀ, Modern Mandaic pronunciation: [ˈɑdam ˈkæsjæ]; also referred to using the portmanteau Adakas ࡀࡃࡀࡊࡀࡎ or Adakas Ziwa in the Ginza Rabba) means "the hidden Adam" in Mandaic. The hidden Adam is also called Adam Qadmaiia (ࡀࡃࡀࡌ ࡒࡀࡃࡌࡀࡉࡉࡀ, "The First Adam"). In Mandaeism, it means the soul of the first man. He is also identified as Shishlam, the primordial priest.

Among the Mandaeans, Adam Kasia means the soul of every human. Adam Kasia shows many similarities with the Jewish idea of Adam Kadmon.

Prayers in the Qulasta, such as the Asut Malkia, also refer to Adam as "Adam the First Man" (Adam Gabra Qadmaiia). The Thousand and Twelve Questions, a Mandaean priestly text, also refers to Adam Kasia as Adam-S'haq ('Adam-was-bright'), Adam-S'haq-Ziwa, or Adam-S'haq-Rba, who is described as the father of Shishlam, the archetype of the prototypical Mandaean.

The wife of Adam Kasia is Hawa Kasia ('hidden Eve'), also known as Hawa Ziwa ('radiant Eve') or Anana Ziwa ('radiant cloud').