| Underneath 1. (adv.) Beneath; below; in a lower place; under; as, a channel underneath the soil. 2. (prep.) Under; beneath; below. Thesaurus Entries bed, bedrock, belly, below, beneath, bottom, bottom side, breech, buttocks, clandestine, covert, downside, fundament, furtive, hardpan, hole-and-corner, lower side, lowest layer, lowest level, neath, nether side, nethermost level, rock bottom, sole, stealthy, subordinate to, substratum, surreptitious, under, under-the-table, underbelly, undercover, underlayer, underside | ![]() |