Or search: gayly, merrily, mirthfully
2 Syllables: SU
3 Syllables: SUU
4 Syllables: USUU
5 Syllables: UUSUU
6 Syllables: UUUSUU
7 Syllables: UUUUSUU

Found 96 words across 6 groupings. Skipped 1 excess word of a similar stem.