Synonyms to underbuilding

fundament, backside, base, basement, basis, beam, bearing wall, bed, bedding, bedrock, behind, belly, bottom, bottom side, breech, buttocks, derriere, downside, floor, flooring, fond, footing, foundation, fundamental, ground, grounds, groundwork, hardpan, lower side, lowest layer, lowest level, nether side, nethermost level, pavement, posterior, principle, radical, rear, riprap, rock bottom, rudiment, rump, seat, sill, solid ground, solid rock, stereobate, stylobate, substratum, substruction, substructure, terra firma, underbelly, undercarriage, undergirding, underlayer, underneath, underpinning, underside, understruction, understructure, AF, ab ovo, abecedarian, aboriginal, antenatal, audio frequency, austere, autochthonous, axiom, bare, basal, basic, basilar, beginning, bench mark, budding, cardinal, cardinal point, center, central, chaste, chief thing, climax, component, constituent, constitutional, constitutive, core, cornerstone, creative, crisis, critical, critical point, crucial, crux, dominant, element, elemental