Or search: provably, incontrovertibly
2 Syllables: SU
quandary
3 Syllables: SUU
comedies, comedy, consciously, constancy, constantly, Conversely, Lombardy, quantities, quantity, wantonly, wrongfully
4 Syllables: USUU
despondency, geometry, inconstancy, subconsciously, unconsciously
5 Syllables: UUSUU
horizontally

Found 18 words across 4 groupings.