Or search: arbitrarily, haphazardly, indiscriminately
3 Syllables: SUU
amnesty, angrily, Antony, anxiously, bankruptcy, Chancery, fantasy, frantically, handsomely, manfully, manganese, scantily, thankfully
4 Syllables: USUU
financially, philanthropy, substantially
5 Syllables: UUSUU
instantaneously, understandably

Found 18 words across 3 groupings.