2 Syllables: SU
beauteous, bruises, Brutus, Buddhist, chooses, coolest, coolness, crudest, dubious, Dumas, Eustace, fewest, fluids, foodstuffs, fruitless, fuses, humans, Judas, juices, Julius, looseness, Lucas, Lucius, lupus, mucous, mucus, Muses, newest, newness, Newton's, nucleus, plumage, Rubens, rudeness, rudest, Rufus, ruins, ruthless, sewage, shrewdness, smoothness, soonest, studious, toothless, usage, useless, uses
3 Syllables: USU
ablutions, acuteness, allusions, aloofness, conclusions, Confucius, confusions, delusions, diffuses, effusions, illusions, intrusions, produces, refuses, solutions, Vesuvius
4 Syllables: UUSU
constitutions, contributions, distributions, evolutions, executions, institutions, prosecutions, resolutions, revolutions, substitutions
Found 73 words across 3 groupings. Skipped 1 excess word of a similar stem.