Adi Murti is a term used to refer Hindu God Vishnu. The term Adi Murti is used to the primordial source of energy responsible for all animate and inanimate in the universe. This only being is indefinable but for the sake of devotees, ancient seers used terms like Adi murti and Adi Shakti to give form to the formless.
Dattatreya is also refered as Adi Murti in certain texts.
Vishnu seated on the coils of Serpent Adi Sesha is also believed to be Adi Murti.