2 Syllables: SU
actress, adage, aptness, Atlas, axis, badness, baptised, Baptist, blackest, blackness, cabbage, cabinets, cactus, captious, factious, flatness, gaseous, gladness, gratis, hapless, happiest, lapis, lattice, madness, Madras, magnets, Magnus, mattress, package, Sabbath, saddest, sadness, slackness, status, taxes
3 Syllables: SUU
3 Syllables: USU
4 Syllables: UUSU
Found 40 words across 4 groupings. Skipped 2 excess words of a similar stem.