Synonyms for Foundational:

adj.

•bottom (adjective)
base, bottom, lowest, primary, basal, underlying, elementary, basic, radical, fundamental.
•elementary (adjective)
elemental, essential, clear, plain, fundamental, original.
•fundamental (adjective)
bottom, elementary, prime.
•primary/prime (adjective)
simple.
•pure (adjective)
clean, unblemished, formative, basic, uncluttered, virtuous, plain, unadorned, guiltless, elemental, unalloyed, purebred, nascent, blameless, bare, simple, fundamental, unsullied, decent, primal, faultless, austere, monolithic, indivisible, spotless, undiluted, prime, untarnished, irreducible, angelic, chaste, white, aboriginal, primary, stainless, untainted, clear, sinless, pure, unadulterated, undefiled, atomic, essential, Simon-pure, immaculate, honorable, elementary, innocent, stark, basal.
•radical (adjective)
primal.

n.

original, radical, surface.

Other synonyms:

radical, original. •Other relevant words:
radical, original.