Synonyms to undermost

basal, 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, bedrock, aa, abyssal rock, basalt, base, basement, basis, bearing wall, bed, bedding, belly, block lava, bottom side, brash, breccia, breech, buttocks, conglomerate, crag, deepest, downside, druid stone, festooned pahoehoe, floor, flooring, focal, fond, footing, foundation, fundament, gneiss, granite, ground, grounds, groundwork, hardpan, igneous rock, indispensable, infrastructure, lava, life-and-death, life-or-death, limestone, living rock, lower side, lower strata, lowest layer, lowest level, lowest point, magma, mantlerock, metamorphic rock, monolith, nadi