Or search: rarity, density, thinness, dimension, denseness, slenderness
3 Syllables: SUU
foolishly, musically, nudity, unities, unity, uselessly
4 Syllables: USUU
annuities, annuity, communities, community, community's, conclusively, confusedly, exclusively, gratuity, immunities, immunity, impunity
5 Syllables: UUSUU
assiduity, contiguity, importunity, incongruities, incongruity, incredulity, perpetuity, perspicuity, superfluity, unobtrusively
6 Syllables: UUUSUU
discontinuity

Found 29 words across 4 groupings.