Cumbersome rhymes with:
adventuresome, bothersome, tiresome, venturesome, adventuresome, ambisone, atheism, awesome, axsom, balsam, bassam, beanblossom, belkacem, blossom, bloxham, bloxom, bloxsom, bothersome, bransom, burdensome, busam, buxom, cataclysm, chisam, chisom, coaxum, doersam, ehrsam, epsom, fearsome, flotsam, folsom, fossum, foursome, fulsome, grissom, gruesome, gypsum, handsome, hansom, hersom, irksome, isom, issam, kassem, kissam, langsam, loathsome, lonesome, malsom, maxam, maxham, maxim, maxxam, meddlesome, nettlesome, newsome, opossum, possum, quarrelsome, ransom, ransome, rexham, russom, russum, samsom, sansom, sissom, tasm, threesome, tiresome, transom, troublesome, twosome, vanrossum, venturesome, wassom, wassum, wearisome, wholesome, winsome, wixom, worrisome
Cumbersome sounds like:
comparison, compression, conversion