Um rhymes with:
ancrum, baucum, become, bluhm, boyum, brum, brumm, bum, chum, clum, come, crum, crumb, crumm, cum, drum, drumm, dum, dumb, dumm, exum, from, frum, glum, grum, gum, gumm, hmmm, hohum, hum, humm, klumb, krum, krumm, krumme, kumm, lum, lumb, lumm, maam, mccrum, mccrumb, mum, mumm, mumme, narum, numb, pflum, plum, plumb, rum, schrum, schum, schumm, scum, sharum, shrum, shum, slum, some, strum, stum, stumm, succumb, sum, swum, thum, thumb, thumm, umm, yum
Um sounds like:
ueno, uma, umana, umm, un, una, uneo, uni, union, uno, unum, unwin, uyeno