primordial
Definitions
Existing at or from the beginning of time; primeval.
In the earliest stage of development; rudimentary or basic.
Fundamental or essential to the constitution of something.
Examples
The primordial soup of the early Earth is believed to have contained the basic building blocks of life.
Deep within the forest, he felt a primordial fear that had been dormant in his ancestors for centuries.
Synonyms
ancient primal original primeval earliest pristine fundamental