Or search: unsoiled, unstained
2 Syllables: SU
audit, clotted, cockpit, dotted, frosted, jotted, knotted, lauded, nodded, opted, optic, Ovid, plaudits, plotted, potted, prodded, Roderick, rotted, spotted, squatted, topic, toxic, tropic, trotted
3 Syllables: USU
acknowledged, allotted, applauded, aquatic, chaotic, defrauded, despotic, erotic, exhausted, exotic, hypnotic, narcotic, neurotic, quixotic, spasmodic
4 Syllables: UUSU
episodic, idiotic, microscopic, patriotic, periodic, philanthropic, superadded, unacknowledged
5 Syllables: UUUSU
antibiotics

Found 48 words across 4 groupings. Skipped 4 excess words of a similar stem.