Underhill rhymes with:
summerhill, anthill, barnhill, berryhill, brookehill, broyhill, cahill, coghill, dunhill, foothill, gladhill, gledhill, greenhill, halfhill, hemphill, mccahill, mcmahill, molehill, parkhill, polhill, rockhill, sandhill, sawhill, scahill, stanphill, stodghill, stonehill, summerhill, tannahill, thornhill, tuthill, whitehill, whittinghill
Underhill sounds like:
underlie, underly, unnatural, unnaturally