Or search: purity, naivete, naivety, cleanness, whiteness, innocency, naiveness, sinlessness, blamelessness, inculpability, inculpableness
2 Syllables: SU
difference, different, interim
3 Syllables: SUU
Chrysostom, cinnamon, citizen, discipline, dissonance, filament, immanent, immigrant, imminence, imminent, innocent, irritant, ligament, militant, minimum, silicon, vigilance, vigilant, virulence, virulent
3 Syllables: USU
deliverance, indifference, indifferent
4 Syllables: USUU
ambivalence, ambivalent, belligerent, Dominican, equivalence, equivalent, habiliments, itinerant, magnificent, munificence, omnipotence, omnipotent, participant, predicament

Found 40 words across 4 groupings. Skipped 11 excess words of a similar stem.