Nethermost

(a.) Lowest; as, the nethermost abyss.

Thesaurus Entries

ab ovo, aboriginal, basic, basilar, beginning, bottom, bottommost, central, constituent, constitutive, crucial, elemental, elementary, embryonic, essential, foundational, fundamental, generative, genetic, germinal, gut, in embryo, in ovo, lowermost, lowest, material, nethermost, of the essence, original, pregnant, primal, primary, primeval, primitive, primordial, pristine, protogenic, radical, rudimental, rudimentary, seminal, substantial, substantive, underlying, undermost