Or search: thane, voter, freeman, elector, civilian, repatriate
2 Syllables: SU
difference, different, interim
3 Syllables: SUU
Chrysostom, cinnamon, citizens, diffidence, diffident, diligence, diligent, discipline, dissonance, filament, immanent, immigrant, imminence, imminent, innocence, innocent, irritant, ligament, Michigan, militant, minimum, silicon, vigilance, vigilant, virulence, virulent
3 Syllables: USU
deliverance, indifference, indifferent
4 Syllables: USUU
ambivalence, ambivalent, belligerent, Dominican, equivalence, equivalent, habiliments, infinitum, itinerant, magnificence, magnificent, munificence, munificent, omnipotence, omnipotent, participant, predicament, significance, significant
5 Syllables: UUSUU
insignificance, insignificant

Found 53 words across 5 groupings. Skipped 11 excess words of a similar stem.